I still don't think adding players would be of any benefit to the game. Keeping the numbers as they are makes the coach have to weigh how they want to set up their teams. They may be able to create strengths, but they also create weaknesses. The match-ups of players in game planning are to take advantage of the other teams weaknesses, if every team can create a spot for a specialist or overload on one position, then game planning again becomes less of a factor. The game would not benefit from every team having specialists all over the field. The craft of building the team would be accomplished by selecting the correct players for your system and minimizing the weaknesses.
Fix recruiting to get rid of the auction style, and maybe rework how players can be changed to new positions (recruits are more moldable) but leave the numbers the way they are.