The capability of the V-22 has been needed by the Corps for a while (as evidenced by the copious number of CH-46s they're using in Iraq right now). The actual piece of equipment that is the V-22...well, that's still open to debate. The Osprey still has, and will continue to have unavoidably, technical issues that may make it ultimately unsuitable as a transport system.
At least, that's according to the rotor-heads I've talked to...