For me the main problem with career mode isn't the lack of new superfical features (i.e. manager market), but the fact that AI opponents seem to have gotten worse year by year, in terms of how fun it is to play against it, specially when they attack. For reference I've played mainly on ultimate and also some games on legendary. Even with "dynamic behaviour", all teams pretty much play the same way, and AI controled players also behave very similarly : they all jockey perfectly, they all turn on a dime, their first reflex is always to turn back and pass it backwards, and they always attack in the same way in transition (pass to the striker, who then passes it over the top to a winger). To be clear, I'm not complaining about the game being too difficult, or too easy, but that it is fundamentally boring.
I've been playing career mode since fifa 11, and I remember a time when you could notice basic differences between teams in terms of pressing and passing. Also I don't really notice something as basic as AI opponents actually changing their behaviour when trailing, sending more players in front and pressing like crazy. Admittedly, even then games got stale after a while, but at least there was some enjoyment to be had.
I feel that AI behaviour has reached a new low this year, and it's a shame because the game mode has so much potential, but it is ruined by the actual gameplay. The more I play, the more I feel that there is something fundamentally wrong that no amount of tinkering with sliders can save (and even if it can make it better, it shouldn't be the player's job to do so!!!) I don't know if it's from the new roles system, but I do not for sure that AI opponents, specially attacking wise, are very repetitive in their actions, completely lack individuality and never give the illusion of behaving in a "human like" way.