I would like that, there's literally no downside to this and it streamlines the gameplay experience. Give the player the option to stop the evolution in-battle and everyone wins.
The downside is wasted development time on a pointless feature that will rarely occur.
I really doubt it would take much time to code.
Depends on how you look at it - making it a full mid-battle event would mean it looks just like another attack, but your Poké evolves. Just a special effect covering the Poké, and the switch out the model while you can't see anything. THAT would be pretty easy. But if there's going to be like before (with it's own screen), it would mean they have to call the evolution event and store all the battle variables meanwhile. After the evoluion, the battle would require a reload while skipping the initialisation ('NPC wants to batle!', throwing the balls 'n stuff), which means the system has to serve you a loading screen until the battle has been reloaded and your (now evolved) Poké is on the field. Sounds simple, but requires a lot of work to do.
I was picturing it more like the former than the latter, quick and easy. Just make it a prompt in battle: Charmander grew to level 16. What? Charmander is evolving! Allow Charmander to evolve? Yes -> Charmander just evolved into Charmeleon! No -> Charmander stopped itself from evolving.
Something like that.
Yes. But! Allow EXP for opponent Pokemon, too.
This as well, I'd love for opponent's Pokemon to evolve mid-combat too. --- http://backloggery.com/lunarroar Official Abra of the Pokemon X/Y Boards