Pokémon is a terrible game to play competitively because, as stated, there are moves and Pokémon that are deemed unfair and are banned. There is no quality balancing, and the vast majority are useless outside single player, and plenty aren't even good there.
Now, calling it repetitive is subjective, some people don't take issue with the breeding and EV training the old fashioned way. During Gen III I sank into all of it, the full metagame experience. Boxes filled with mons that weren't the right nature or something. But I also played a lot on... Well, I can't remember the name of it, like Pokénet or something? Anyway, it was an online battling program, and you could max out a team with which to fight. I was on that all the time, and while there were a lot of teams full of Kyogre/Groudon/Speed or Attack Deoxys/etc., there was plenty of expirementation with not-over powered. I'm not sure where I was going with this. Oh, repetitive. Yes. Basically it's only as repetitive as you make it and how much you want to play with ideas in game. I can see the argument that it can be painfully slow, but if you know what your looking for, you've cut a great deal of the issue off. Ramble ramble ramble.
As far as the actual battling, it's not all that much different from good competitve games. Let's compare it to other games with reasonably large competitive communities - Super Turbo, well Street Fighter in general, Smash Bros. Brawl and Melee., and meybe an FPS They all have a great deal going on under the hood that you don't really need to know to play - easy to pick up, difficult to master, they all require, at high level play, a knowledge of the moves at your disposal, your opponents disposal, what they (the opponent) are likely to do, how you should respond, the yomi idea that Sirlin has talked about a great deal. To say that no skill is needed in Pokémon is not necessarily wrong, it's more it doesn't need the same kind of skill you would use in SF or Smash or say, Counter-Strike. They involve a lot of muscle memory, timing, and knowing what to do in that sit. Pokémon Really only removes the muscle memory. And from my experiance, it's not the inability to pull of that last Shoryuuken or because you couldn't hit that Monkey Punch that caused the loss, but rather you did the wrong Move at the wrong time. What I am trying to say that if it's not the ability to do the move that matters, Pokémon could be a great competitive game. I mean, people still play chess, and you don't have to juggle bowling balls while blindfolded to castle.
Negatively, Pokémon really runs into the problem of having only a small number of viable mons, and those only have a few movesets that you will ever see. And I say runs into a Problem like '100 mph headlong into wall' problem. They can't be beaten except by another of the high tier mons. There's a reason most every team, if Legendaries are banned, you'll end up seeing so many SkarmBliss, Weezing with Will-o-Wisp, or whatever super mons that have come from the last few, I haven't kept up to date as much. Or Fox in Melee, or Dedede/Snake/Meta in Brawl., Sentinal in MvC2, and it looks like Storm/Sent/Mags is where 3's heading again. And while OHKO moves are not bad, but in a game where dodges or blocks are based on rng, it's impossible because there will be someone to stack the numbers. Yeah, DK can pound you in the ground, then hit you with a bat, but there is still more you can do to counter it. Number based games aren't bad, OHKO aren't bad, putting them together leads to god tier or ban, niether is good.
Pokémon has many features going for it to be potentially a great competitive game, but falls apart with it's massive roster, poor, if any, balancing, and game mechanics that undermine the stratagy it could have.
