We all know it's competitive flaws by this point, excellent offensive typing with practically no defensive utility, to the point where having an ice type coverage move is preferable to using an actual Ice Type Pokémon for the most part, with exceptions for some of the legendary ice types (Kyurem being the most notable). The worst part is that Ice types almost always seem to be given a defensive focus despite the clear flaws defensively, with the few offensively oriented ice types tending to perform way better, eg. Weavile.
However, i'm more here to talk about in-game usage, and how the type tends to be used poorly in that regard.
Starting off, in Kanto, yhe Ice Type specialist in the game is Lorelei, and she is quite possibly the best showing from an Ice Type specialist, with there being no Steel type to resist the attacks, no fire type resistance to ice and an extra Water resistance that they can use. The problem is that she's an elite four member so you have had plenty of time to prep up a team, along with her team having a Slowbro on it for some reason. Forgivable though, since gen 1 does this pretty often and she's not the worst offender. Looking at you, Bruno.
In Johto, Pryce is the official 7th gym leader, though he can be fought as early as your fifth gym. Again, he has a non-Ice Type on his team in Seel, though this one does at least evolve into an Ice Type. In battle he's generally unimpressive, with his Piloswine being the only really interesting member of his team. I've honestly never had any trouble beating him, even when I did go for him as my 5th Gym Leader since I wanted to get the Red Gyarados and EXP Share earlier. The big problem he falls to is his entire team consists of only using Normal and Ice moves, and Rest in gen 2. In HGSS they fix this slightly by giving his Piloswine Mud Bomb but it's a relatively weak move coming off of base 60 Spa.
In Hoenn, we have another Elite 4 member, this time in Glacia. and her team is quite frankly a mess. In the base RSE, she has two Glalie, two Sealeo and a Walrein, with the most threatening moves she uses being Light Screen on the first Glalie, having a Hail/Blizzard combo on one of her Sealeo, her second Glalie having Explosion, but only in Emerald, and her Walrein has a pretty competent moveset of Surf/Body Slam/Ice Beam, with Sheer Cold thrown on there just in case you're a bit underlevelled. ORAS changes her Sealeo for two Froslass instead, both of them having a Hail and Snow Cloak combo. Overall she seems designed to be more annoying than challenging, with most of her mons having status moves like Attract, Encore and the aforementioned Light Screen and Hail. Not a great showing though.
Next is Sinnoh, a region based on Hokkaido in North Japan and shown to be rather cold, especially in Platinum. You'd think that'd make Ice Types power up a bit, and while they got some decent improvements in the form of Snow Warning being desperately needed, the in game usage remains pretty poor. The Ice Type specialist in this game is Candice, another 7th gym leader, and she is once again not great. Her team in Diamond and Pearl consists of a Snover, a Sneasel, an Abomasnow for her ace, and a Medicham. We all know about it and how weird it is, but having an off-typed pokemon in the fourth game when you definitely have enough mons to fill out a 4 mon roster without much issue is not a great look. In addition to this, her actual usage of these Pokémon is similarly lacking, with Medicham probably being utilised the best with Bulk Up, Force Palm and Ice Punch to try and catch a flying type thinking it'd get an easy time. Sneasel just doesnt do anything, having its only ice STAB forcing it to go last and probably get KOed before it does anything, and Snover and Abomasnow similarly dont't do much, with Abomasnow's most threatening moves being Wood Hammer and Grass Whistle. In Platinum, her team was given a pretty well needed upgrade, with Snover being replaced by Piloswine (and with an actual moveset this time, having Earthquake and Stone Edge to take advantage of its attack stat!) Abomasnow being given a moveset upgrade with Water Pulse to maybe be able to threaten the average fire type, and Focus Blast being pretty hard hitting, and Medicham being replaced by Froslass, the mon that is also her Ace. With Snow Warning being set by Abomasnow to have Snow Cloak always active unless you change the weather yourself, and Double Team to make her even harder to hit, she can prove to be annoying, as well as having perfect accuracy Blizzards. If Lorelei isn't the best showing from an ice specialist, I would say Platinum Candice is.
Unova has Brycen, once again, the 7th Gym Leader. Starting to see a pattern now. His team is not overly interesting, having a Vanillish, a Cryogonal and a Beartic. And this time, there's really not a whole lot to be said about him, the team folds pretty easily, the most noteworthy moves he uses are Mirror Shot on his Vanillish and Reflect being there to try and shore up Cryogonal's cripplingly low Physical Defense. Worst part is, in Black and White 2 the closest thing we get to an Ice Type specialist is Ghetsis and his Kyurem being the big villain of the story, with Brycen having retired to focus on his acting career.
Wulfric is the Kalos Ice Type specialist, and this time he's the 8th gym leader! Finally, we're breaking the rule of 7s. He has 3 mons again, this time an Abomasnow (RIP permanent Hail though), Cryogonal and Avalugg. Noteworthy moves include his Abomasnow only having 3, for whatever reason, Cryogonal learning Confuse Ray, and Avalugg trying to be a Curse set up sweeper with Gyro Ball to try to take advantage of the speed drop. Still pretty harmless if you have any competent special attacker, but it tries at least.
Alola is easily the worst off in this department. There effectively is no Ice Type specialist in the region, the closest thing to it is an early game fight against Sina, where she does use exclusively Ice Type Pokémon, however the issue is she only fights the player in the Moon Games. Her teams are also extremely unimpressive, her Ace is a Glaceon that only knows Icy Wind and Quick Attack in both games, with her lead changing based on which version you're playing. In base Moon, she has a Delibird, which only knows Present, and though I can't speak from experience since I played through the Sun versions, it's hard to imagine this team posing a threat unless you picked Rowlet and had neglected to pick up any other Pokémon by this point. Ultra Moon improves this pretty significantly by replacing the Delibird with a Smoochum, and with it having an actual STAB move to use in Powder Snow, along with Pound. This, again, isn't amazing but it's way better than a STABless Delibird and I could see players struggling against it if unprepared. Icium Z is just found partway through the game's "victory road" in Mt Lanakila, for whatever reason.
Galar has Melony, the 6th Gym Leader. Once again, a version exclusive, this time to Shield Version, another game I haven't played at all. Looking at her team though, it seems relatively challenging, with a Galarian Darmanitan, albeit without Gorilla Tactics, and her signature G-Max Lapras being able to set Aurora Veil, though it being her last mon makes that effect feel a bit weaker than it should really. Her Eiscue and Frosmoth both look entirely unimpressive though, with the best thing Eiscue might be able to do being setting up Hail after it's Ice Face is broken to give it a free turn to buff its special defense with Amnesia I guess? Meanwhile Frosmoth has the special defensive side relatively fine and Feather Dance to try and make itself bulkier, but it's just not enough, especially considering Ice Types defensive weakness. Her position is also the earliest of any Ice Type Gym Leader if you're going in the intended order for every game, with only Sina coming earlier. I can't speak for how difficult she is but I doubt it's groundbreaking.
Finally, Paldea has Grusha, another 8th Gym Leader, and the reason I'm writing this dissertation. His team is quite possibly the most disappointing I've fought, if you exclude DP Candice. He has a Frosmoth, which seems to just be there to set up tailwind and maybe get some cheap damage in if you decide to use a special attacker against it, Beartic, which has a surprisingly competent moveset outside of only having 3 moves, with Icicle Crash and Earthquake being pretty strong and Aqua Jet being there to try to beat down mons that were potentially weakened by Frosmoth. Cetitan really has nothing going for it outside of its ability though, with Liquidation there to hurt any fire type that tries to fight it and its Thick Fat ability, otherwise it just has Ice Moves, and not particularly strong Ice Moves at that, those being Ice Shard and Ice Spinner. Finally his Tera Altaria. Outside of it being funny that the quad weak dragon bird became the type that is meant to be its kryptonite, I really don't know what it's trying to do here. It's ability is entirely counterintuative to it being his Ace Mon, though that's not the last time we'll see that being the case, it has Moonblast and Hurricane to try to beat down any Fighting Types you might plan on sweeping him with, though Altaria is probably too slow, and not bulky enough to actually land an attack against those by this point of the battle. Realistically, Grusha was the easiest gym leader I fought in Paldea, and the ice type's design is definitely part of that.
Realistically, this is never going to stop being a problem, the type is balanced around being a great offensive type with weak defenses, though they keep trying to design Ice Types defensively for whatever reason. However, I feel like if they were to give us a proper early game Ice Type specialist rather than constantly putting them as the 7th or 8th gym, they might be able to show their stuff. I'm glad that competitive Pokemon has managed to prove the might of fast, frail ice types as a design with Weavile being strong in every generation so far, and even showing that it's not impossible to make defensive ice types work with Kyurem getting a massive glow up in gen 8, but for in game purposes I feel like Ice Types are simply misused. Maybe one day we'll see Ice Types as an early game objective (not counting Sina since her teams are more handicapped by her using a Delibird in Moon) and i'll be proven right, or wrong. We'll see in time, hopefully.