But 'dodge' (which I think would just be 'Defend') wouldn't necessarily always make an attack miss; it would raise the chance of the pokemon avoiding the attack, but it'd cause them to just take less damage 80% of the time (maybe more than that; the other ~20% would be dodging/avoiding attacks). So you could poison the enemy and then keep on defending, but the enemy could keep attacking and whittle you down slowly, getting you ready for the next pokemon to finish you off. It isn't perfect, but I'm not Game Freak; if they implemented it, I'm sure they'd do a better job than how I explain it.
Well the fix for that is either not letting the in-game trainers level their pokemons' moves, or level them based on your pokemons' move levels somehow. And every move would have level caps; otherwise you could theoretically make any move a OHKO. I imagine that weaker moves like Ember would be able to go up a max of five levels, while mid-level attacks like Flamethrower could go up to three... or maybe every attack goes up to five, but mid-level and high-level attacks like Fire Blast would only increase in their accuracy after a few levels or something like that. Like I said above, I'm not Game Freak, and if they implement something like this, they'd do a better job of it than how I'm explaining it.
I just think it'd make sense; take the idea of 'practice makes perfect' and put it into pokemon, so the more a pokemon uses a technique, the more proficient it becomes at using it. And they only use techniques that their trainers tell them to use, which brings up the idea of the bond between trainer and pokemon having to do with the new mechanic. The only other thing I can think of is something to do with the Happiness stat, but who knows what that could be? Stat/EV boosts if a pokemon is happy? I have no idea, but that seems foolish, like something they could've implemented back in Gen 4 or 3. I figure that if they're mentioning it now, it'll be something groundbreaking, not something related to an invisible stat.
Or it could be a total curveball, and they're gonna make attacks dual-typed, or triple-typed pokemon, which would be the stupidest thing ever. No one can really say at this point...
I seems to me that you have missed a vital point in Pokémon. Yes, practice makes perfect! By EV training, gaining a level, learning new skills. As previously stated, ember already has an "evolution", there's no rational reason for GF to add something as attack evolution. Also, the dodging system has been implemented since day 1 of Pokémon. Its what the Accuracy and Evasion stats are for! Basically, what happens when an attack "miss" is that the opponent dodged it. The game even tell you that "… avoided the attack". I can see that you have put lots of thought into your idea, but it really isn't right for Pokémon.