If that compromise were to be the best option (and it's probably the best suggestion that won't overload the game charts and possibl put people off), then missions that perhaps wouldn't be added, would be perfection, die hard (obv), stealth, and possibly keep the pace. I think removing the sphere collector missions would also be a good idea too, unless someone disagrees.
There are 14 of each mission type, these are the ones I propose to keep:
Ring Collector
Rampage
Item collector
Special Trial
That would leave 56 missions in total. How does that sound?