First impressions of new Winning Elevens should never be trusted. They always play differently and are difficult to adjust to. People don't feel comfortable playing and can be quick to criticize the game. Give them a week and suddenly everyone is singing its praises and deeply appreciative of the changes. Then, however, the new version comes back and people look back at the previous one with distaste. It's a constant cycle. I've trained myself not to become a part of it and not make up my mind immediately.
I've played a couple dozen matches of WE8 now and I still have a difficult time of expressing how the overall game has changed without resorting to finer details. The passing is much better. You can hold X to fire a pass to distant teammates along the ground. And through passes are now extremely dangerous. CPU players make more frequent and intelligent runs. They're also longer (ie, L1 + X --> instead of returning the pass, pass it to someone else, who can send it to the person who you initially sent running). Dribbling is also much better, though difficult to get used to. I feel like I've got more control over the ball (tap R2 once and you quickly stop dead, but can cut away quickly - it's a very fun and realistic way to beat defenders and maintain possession), but the ball doesn't stick to the feet as easily as it did before. The AI is also noticeably improved and is better at checking, so possession can never be careless.
My one complaint is the slowdown. When there's a lot of activity inside the box, the game starts to chug. But turning the crowds to 1 star effect has seriously helped the issue. I can play at the Wide angle (furthest out) and the framerate doesn't interfere much.
5 star is more difficult so far. To the point where a loss might be because I wasn't good enough to win, rather than just being unlucky. Mostly because I haven't gelled with the game yet, but the AI is definitely better. 6 star should be interesting.