It would be neat to be able to do the run/pass package plays that are becoming popular in the NFL the past few years. Also it would be cool if the play formations and play design was more flexible allowing for the ability to have 6 or 7 offensive linemen on the field in a 'jumbo' package or the Vic Fangio staple of the 2011-14 49ers the 2-4-5 defensive front. Being able to select the specific personnel groupings you want on the field would be a lot of fun and more realistic as many NFL teams have guys like Calais Campbell who play both DE and DT.