When it comes to character development though, most people automatically think about evolution like that's the only way for Pokemon to develop. And the funny thing is that once a Pokemon is fully evolved, if that Pokemon develops problems (like Torterra's losing streak for example), people try to gloss it over and don't offer ways of solving said problem. That only confirms my theory that evolution is viewed as the answer to every problem a Pokemon may have among the fanbase. Thankfully, the writers don't think much of evolution. That's probably the only thing I have in common with them lol. *Goes to her Oshawott shrine and thanks the lord that Oshawott's not evolving*
I reckon 80% of development SHOULD be evolution! You train your Pokemon, they get stronger, they evolve. This isn't Digimon, where they can de-evolve again so that they can be cutesy when they are out of battle! Pokemon are supposed to evolve. The writers distaste for evolution can account for a good portion of the staleness in Ash's team. Which are two least favourite teams with fans? Johto and Unova. These are the least evolved teams also. Which teams got the most stale? The same two. Why? Because if the writers weren't in the mood to bother developing Ash's team so they stay unevolved, they lack personality and they don't learn many new moves (or decent ones- NOT tackle and water gun and crud like that). In Sinnoh, the writers made a real effort to develop his team, even though Torterra was shafted in the end for Infernape. The result was evolution, new moves, character development and a non-stale team. Unova has been dire on all of those counts.
In Unova, 7 Pokemon have evolved under Ash's care, the exact same number as in Sinnoh when he had three less team members, so the number of evolutions have been divided between more Pokemon. He should have had at least 9 evolutions with 9 new Pokemon, I think.
The root cause is the writers being too flaming lazy to develop Ash's Pokemon. If Snivy evolved, it would be incredibly refreshing and she would become instantly more popular. I, for one, am fed up of the writers repeating themselves over and over. One Bulbasaur was enough, Snivy doesn't need to be its clone. Serperior is superior, face it. As for Oshawott... lets just say I'm looking forward to the 6th gen when we can be rid of him!
The BW saga has been all about regression. Firstly, we have regression in Ash's development as a character and as a trainer, as evidenced by him becoming babyish again and getting less far in the league than in Sinnoh. Secondly, we have a regression in the writing, with Ash's team going from pretty cool in Sinnoh to absolutely and thoroughly atrocious in Unova, with a disgracefully low amount of development. Also, the terrible writing of the league, gym battles, rival interactions, 'Don tournaments' (what a waste of potential) I could go on forever, but I think I've gone on enough as it is!
BW is objectively the worse saga since Johto, in which we saw the same level of carelessness from the writers, who for absolutely no reason, despite being given loads of time, refused to evolve Ash's team much at all and didn't develop it much either. Pikachu also hogged battles (EVERY single gym) which is a clear indicator of the writers opting for the easy way out, re-using Pikachu stock animation and not having to come up with any new strategies.