I would love a "Be A Manager" type of mode. I know career mode is basically this, but I don't have any attachment to the manager himself. I'm playing career mode for the team and rarely do I jump teams.

I'd love to be able to design a manager's features the way you do with with a Pro in Be A Pro, even down to appearance. Perhaps even going so far as to develop a backstory (former professional or not, position, disposition, what level of play, etc.). This could be combined with certain skill trees and abilities like contract negotiation, youth recruitment, tactical knowledge, negotiating with the board, talking to the media, player training, and you could hire your own staff that you could bring with you when you move on to bigger things.

I just think it would give more incentive for people like me to stick with a career mode in the "world" of Fifa instead of starting from scratch every time you want to play with Fifa 16 coins, but this would just be an alternative mode to career mode, not eliminate it. Also I know the skills and abilities would need some more work from what I simply stated, but those were just ideas to get started, not anything fully thought out.

I have a bunch of friends who come over to play FIFA, and while it's fun to play 1v1s and 2v2s, it is even more rewarding to play on the same team. You can do this on seasons and FUT, by adding a guest. However, you are limited to 1 guest. This is understandable for gamemodes where both players control the whole team, but it would be amazing to have an option to play on the same team with three guests.

This would be an amazing feature for Pro Clubs.
Three guests, along with a system where players can save their Pros on the EA servers, and access them on any console, just by logging in.

Most people who make Pro Clubs wishlists want custom kits and a training arena, and while the latter will have an actual impact on how you improve, custom kits adds very little to the game. A guest feature, however, would make Pro Clubs the best way to get new players interested in Fifa, and to bring the game to a new level of couch co-op awesomeness.