The running theory on the 'swim board is that 21 will go back to his online business; I'm thinking he'll either turn OSI/Sphinx or he'll start Arching as "The Viceroy".
My "wish list" for Season 5:
-- Kill the moppets (they were funny for all of, what, five minutes?
-- Dean ends up going Arch on someone (Raven)
-- Monarch and Mrs. The Monarch really need to get some resolution with the whole Arching Doc. angle and reveal what's got him so pissed at Rusty; the running gag of it not knowing has sort lost some of its shine.
-- Mrs. The Monarch seems to be more ruthless than The Monarch they need go somewhere with that.