WEBF - look at how the Osprey folds its wings and props, then try to imagine how that would work with the E2 radar above it. Simply terrifying. I suspect the Osprey may well have a higher fuselage height than E2 which would make it very difficult to fit in the hangar with a radar on the roof. Navaleye is also bang on - its the ability to get to station quickly (or accompany a strike) that is important. I don't think a 240kt cruise in V-22 would really cut it for the latter. More to the point no-one will ever fund it - just sorting out the CG issues in translation would be a major programme.
Presumably Ark is to cover for Ocean during her only major refit (due next year I think?). VVHA is right - its fitting the hundreds of Royals in, sorting the passageways for use as assault routes and providing ammo issue points (safely) that are the embuggerance factors. Ark operated well (with the known drawbacks) in Telic - if only we were looking at a sensible maritime support helo, with rotor fold, EMI sorted, compatible materials and everything................