I like both ideas about trading and roster limits.
In keeping 20 players as a minimum, that still keeps with the idea of the franchise theme, and allowing trading makes it much more intersted.
In the other two-team league, it kind of gets boring after the draft, since all you can do is add/drop, while I see a lot of deals that could happen to help both teams.
I like a 20 player franchise roster floor, and trading.