If we really learned something from EA's products over the years then it's definitely the trailers always look fantastic while the actual gameplay is probably a bit different story. I won't have big expectations in that area.
However would love to see some upgrades in the Manager mode. Full Champions League license, bigger database of players with their actual look and stats, way more complicated means of negotiating and bidding wars, stuff like that... Stadium upgrades, academy improvements, press conferences. Manager mode should be a way to go.
They should focus on practical improvements. If someone tells you that their new game will be better because 'the next gen' it's more likely that they're full of.