Anyway, it sounds like jsh has the same issues with competitive Pokemon that I have. Grinding is no fun, Stealth Rock breaks everything, it's impossible to get new players into it because there's so many stats and type match-ups and things to memorize, and who can learn what moves and stuff. At its core it's a pretty cool game: you make decisions simultaneously, you're always trying to out-guess your opponent, it's like a turn-based fighting game. But it's so complicated and I think it's just not designed for competitive play. It probably wouldn't be hard to make a Pokemon-like game that is much more interesting for competitive play, but then you'd have to get people to start playing it before anyone cared about it.
FWIW, Sun/Moon's battle UI includes a bit that tells you the type effectiveness of your moves. IIRC, you need to do something to trigger it, but I'm not sure what... test a move out once on the opposing Pokemon? Catch the Pokemon so you can confirm its typing? Something like that. When this was revealed, a portion of the fanbase freaked out about how GameFreak was continuing to dumb down the game. Of course, this is certainly intended to make it easier for young kids and those who don't have the time or memory to know all the type matchups, and most fans recognized it and embraced it.
Likewise for the ExpAll item in XY. It makes it a lot easier to level up the entire team, making grinding much less of a chore. A few users complained that it made the game too easy; most realized you could just turn it off and it was a valuable tool for raising up new teams. In fact, a lot of stuff introduced in XY simplified things for competitive play. Destiny Knot and various changes to breeding mechanics made it so much simpler to breed "perfect" Pokemon; XY was the game where I actually got into all that. Not that I competed in PvP; I just wanted great Pokemon to face off in the Battle Maison.
How much of an impact do IVs have? I agree that, while it's a cute idea for single player (all pokemons are unique!), it's completely idiotic for a competitive format.
That's what I liked about Pokemon Stadium. At least we are all on an equal footing.
Stat calculator here. Weirdly, it says "DVs" instead of "IVs" but they're all set at 31 by default so I know that's what they meant. Hopefully the rest of the programming is alright.
(Edit: they were known as "determinant values" in gens I and II, apparently.)
For a level 100 Mew (stats of 100 across the board) with a Docile nature (no + or - to any stats), max IVs gives 341 HP and 236 for everything else. 0 IVs gives 310 HP and 205 for everything else. So it looks like each IV is exactly 1 more point for the stat at level 100.
At level 50, max IVs gives 175 HP and 120, and 0 IVs gives 160 HP and 105. So in that case, each IV is only worth half a stat point. I believe official matches are typically capped at level 50.
With positive natures, the differences are multiplied by 1.1, so IVs can make a maximum of 34 points difference in a stat at level 100 or 17 points at level 50. This can be further multiplied by various items or other boosting effects.
I'm not an expert but this doesn't sound like
that big a deal usually. Sometimes it can mean the difference between fainting and a clutch survival, but it seems like small potatoes to me. The one big exception to this is Speed. Whoever is faster goes first, so even a single point of increase can make the difference.