This is a bit ridiculous, but would it pretty fun if you could unlock a second or third BIT to command, in addition to your main.
Granted, the Secondary BITS would have several limitations. Such as only using one specific type of chip (Ex: BBX will only use Lightning-Type Chips, NJX uses Sword-Type and Shadow Parry, DDX uses Blast-Type), MUST have said chips in your folder for the Secondaries to use or else they will only Auto-Fire, buffs/heals only apply to your Main BIT, take up 2 or 3 points of Memory on the board, and you cannot have two copies of the same BIT; if you chose BBX as your Main BIT, the secondary version is unobtainable, always. Oh, and they cannot Style Change.
As for the other idea, new playable BITS like the characters that appear in Freeze, SuitUp, CntOnMe, RevUp, and BrnBrnB. T'would be a waste of good character designs to be limited to just summoning animations.