I'm a bit surprised he hasn't ended up at Newcastle.
It's hard to rediscover your form after taking such a nose dive like Coutinho has. Even the Bayern loan never really worked out as it should and so Villa is probably his level now. I think he will be a success, he won't get back to what he was but he will have his moments and the seals will lap it up.
It does seem a bit of a pointless signing in that it's a 6 month loan deal for a club who aren't worried about relegation and aren't going to make Europe, so what's the point in spending so much money on a temporary move?