You can sim draft for the teams you dont like, however draft logic is terrible, team that are stacked at WR will draft 3 wrs in first 3rounds and other horrible stuff like that, what i do is i take that hour or so to draft for every team in the first two rounds (sometimes i go as far as 3) and then i sim the rest of the draft. You do 32 team for these reasons:
1.realistic cuts
2.realistic depth charts
3.realistic drafts
4.realistic player RESIGNING (this one and the 5th point are most important imo, some good teams will not resign their main players for no reason if you play 1team CFM so for example teams like SEA could go from a SB contender to laughing stock of the league in one year in madden just because they wont resign their star players, also those players will then be sitting on FA list and since players have no logic too no matter how good of a player he is and how old and so on and so on he will just sign with the team which has most cap space, so after 1st year you will see teams like Jaguars and Raiders have biggest names in the NFL while the rest of not so good free agents will be left for all other teams which is totally unrealistic cause some real nfl players dont wanna go to trash teams even if they get huge contracts there)
5.realistic FA signing (this one is also very important since you can use actual human brain for this and make decisions to which team should sign which player based on team needs instead of random madden bs)
And yes cpu will trade players even if you do 32team CFM , however i think you need to set other 31 teams to autopilot for that to happen however once again you will always see the same trades from the get go and most of them wont make sense, to give you an example around a year back when i was playing with last season's rosters cpu would always trade away J.Rodgers from Falcons just because they had 2highly rated backs in S Jax and Jacquizz.