Ummm, sorry to spoil the love fest but Shinji Mikami who made Vanquish has left Platinum and started his own studio (Tango Gameworks; which made The Evil Within).
I dont think Platinum has the talent at its disposal to make Vanquish 2 (or make it at the level Vanquish 1)
EDIT - I think they should work on an Okami sequel :)