Its been tested in combat, has the same or better weapons carriage, has better range and most of all it has better speed.
The modest proposal is to bite the bullet and fully embrace the capabilities of the MV-22 by curtailing buys of the AH-1Z and purchasing product improved OV-10's. The big Achilles heel of the AH-1Z when it comes to operating besides the MV-22 is not only its inability to keep up but also its short legs (in comparison). Putting a mixed wing of OV-10's, AH-1Z's and UH-1Y's would cover the bases a bit more effectively than relying on the F-35B and AV-8B to provide escort for the MV-22.
Our current concept of operations will have the AV-8/F-35's busy doing combat air support, fighter sweeps and fleet defense. Escorting MV-22's about the battlefield will be a necessary task that might get left behind among all that work.
But it gets worse. When the CH-53K comes on line it will also outpace the AH-1Z. That means even more work for the fast movers on the MEU.
In my mind the canary in the coal mine occurred during the Libyan War when the MEU was tasked to rescue downed F-15 pilots. AV-8B's were launched to escort the MV-22's. CH-53E's carried a backup force and were escorted by AH-1Z's. Carrying a reinforced squad of Marines isn't exactly a heavy lift for the CH-53 and from what I've been told even those elderly birds can push AH-1Z's to the firewall in order to keep up.
That was the wake up call. Its time. Get some OV-10's out of storage, refurbish them, put in new engines and avionics and lets get the boys at NAVAIR some good work.