I think it would be a good addiction to FM to be able to play a fast game mode. Like playing a whole season in a single day. This would be nice for those times when you've got friends or family staying with you for a week or so. You could have some fun playing FM. Right now FM consumes a lot of time. It's not advisable for offline multiplayer, specially if you don't have a lot of time.
-Simplified tactical system. You would only be able to choose a certain tactic before the game with simple tweaks. For instance, you would have a certain amount of tactics to choose from (4-4-2, 4-3-3, 4-2-3-1, 4-5-1, 3-4-3, etc, etc), and for each tactic you would be able to choose "attacking", "normal" or "defensive".
-No match play. After submitting team and tactic, a process bar would appear followed by the results for all the matches in that day, including yours.
-No time wasting press. Only small stuff.
Among other stuff to make it simple and fast... it wouldn't be about skill as much as luck and signing the correct players. But it could be lots of fun.
I don't know how hard it would be to implement this. Basically I'm asking for another game inside Football Manager, allowing us to choose the standard, for when we want to actually play the game, or the simplified, more arcade like, for those times when we lack the time to play a standard one.