I never post in these threads the hell am I doing
Anyway, it doesn't strike me as particularly of difficulty that any of the above Pokemon just happen to resist both of Sketchy's STAB moves. After all, the likelihood is that a standard attacker set will be able to, grab hold of all the coverage moves it needs, and thus Fire-type moves for Skarmory and Jirachi, Ground-type moves for Heatran and Jirachi, Fighting-type moves to hit all of them for a bit of damage, or even Ice-type moves to hit Dragonite aren't altogether out of our imagination. And beyond this point, I'm not sure what purpose this thread serves. We have given Sketchy a STAB typing that will inevitably make it come up short against certain Pokemon. I don't believe there are any Pokemon currently in existence that Sketchy couldn't hypothetically beat... but again, 4-slot syndrome and our newly created 1-wildcard syndrome limit the extent to which it can exercise its abilities.
Using
Honko's mass damage calculator and assuming a worst-case scenario moveset of Seed Flare/Focus Blast/Blue Flare/Blizzard, though with no investment in SpA, it becomes clear that what can most comfortably stop Sketchy in said ungainable situation are bulky Psychics and Ghosts like Dusclops, Victini, and Deoxys-D... though will not be the case in practice, as Shadow Ball will likely enough be mandatory on all sets, if its movepool is as bleak as it likely will be outside of Sketch. However, interestingly enough it seems that specially defensive Poison-types like Tentacruel and Drapion will likely be quite effective against Sketchy - especially on the special side, which likely will not run Ground-type attacks (though it is, of course, feasible). On the physical side, with a wcs movepool of Power Whip/V-create/Hi Jump Kick/Icicle Crash or Bolt Strike, we have Intimidators like Salamence and Gyarados coming into the fray.
But to get back to the essential point. There are, I believe, two key points that need to absolutely be cleared up here with regard to threats.
1. How fast?
Or, more specifically, "Do we want Sketchy to be faster than Heatran and Dragonite, arguably its two greatest threats, both, one, or neither? I believe that most people are adamant that our friendly neighbourhood ADD Sketch Artist should be below the base 100 benchmark - any higher risks adding too much effectiveness to the basic bulky attacker build. There are only two really serious threats encroaching upon this area - Heatran and Dragonite. How great a threat do we want each of these to pose? Should Dragonite outrun it as well as wall it to heaven and back? Should Heatran be made more of a threat by making it fast enough to outspeed Sketchy?
2. How bulky?
This relates to the potentially contentious part of the "bulky attacker" build - how bulky is bulky? One thing that needs considering for any attacker is its susceptibility to revenge killing. Now, Sketchy is immune to Vacuum Wave, Extremespeed, and Mach Punch, and resists Aqua Jet, so is fairly well-covered on the priority front. Okay, so we have some woe with Bullet Punch and Sucker Punch, but hey, you can't have everything. No, the real worry here comes from the fact that, depending on how fast we eventually make Sketchy, it is going to be in a LOT of trouble from faster stuff trying to crush it. Using
Honko's other awesome tool and inputting values for a Grass/Ghost Pokemon of 252 HP EVs and 100/100/100 stats (go go Celebi) we see that stuff like Latios' Choice Specs Draco Meteor is coming close to OHKOing - this makes absolutely no difference by itself, but it is necessary to look back at all the slower characters such as Hydreigon and Haxorus who have more or less free reign as far as revenge-killing is concerned. Put simply, if Sketchy is too slow and doesn't have the bulk to compensate, it will be absolute dead weight on all teams. So how far are we prepared to go? Well, Gyarados in particular seems to manage all right - though this may be due to all the rain floating around. I would honestly advocate defensive stats of about 90/90/90, such that we have a more or less solid base to work off. I'll admit I'm a little anxious about giving Sketchy very, very good base defensive stats, so I'd say that copying an existing, powerful-but-not-broken Pokemon is the way to go. I am honestly finding it more or less impossible to predict what effect this Pokemon will have on the metagame, so... I can't really say any more.
I'd be interested to hear other people's views on the above two questions.