I will probably get chewed up for this, but Retro Studios should do their own version of Perfect Dark. Not the actual Perfect Dark, of course, but a spiritual successor. I kind of thought that the Conduit series would do this, but it failed and so the opprotunity rests on Retro's shoulders to burden.
I apologize for doing this, but the success of Retro Studios makes me kind of mad that Rare was sold to Microsoft because had they stayed with Nintendo then Retro could have taken over some, or all, of their IPs and made them better. Think about what they could have done with Battletoads, Killer Insticnt and Perfect Dark to name a few.