Well he's nothing like Anderson imo, apart from being a bit small and roundish. The reason I say he's not like him is A) Anderson is mostly an athlete. His actual footballing skills are secondary to his athletic ability in terms of running and good strength and balance. Banega is the opposite in that he has all the football skills but he doesn't have very good speed, he can be a tiny bit lightweight at times but generally gets a freekick when he falls and there are still times when he has great balance too. And B) A couple of seasons ago he was the best midfielder in La Liga outside of Barcelona and Real Madrid. Anderson has never proven himself like that so Banega has personally proven a lot more. The problem is that since then he's had several injuries that have halted his progress and he hasn't hit the same general level he had that season where he was excellent almost the entire way through.
He definitely has had some off the field problems which people have brought up, but as someone who has followed for Valencia for quite a while its my impression that 1) Unai Emery was the main reason. As so many players faced disciplinery action each season for missing training or just falling out with him, etc. When its one or two players you should blame them. But when its half the first team squad who have had issues over a bosses tenure, then he just isnt commanding the right respect 2) There have still been a couple of issues with players after Emery has left, but fewer than there used to be. So I dont think Valencia is the best environment for inspiring the team to be professional.
So while its something to consider that he has indeed fallen out with Emery and has been fined by the club for not turning up for training and also going out drinking the night before a game with some other players, I believe those were the issues, I think you have to take into consideration that several other players made the same mistakes. At a new club with a tighter, more professional approach I'd expect him to be able to nuckle down especially as he can no longer play the young player card.