Outside of Legs none of these are accurate.
I support Osprey with an Apache and we're slower than the Cobra... all he needs support on is the actual Infil/Exfil we arent escorting anything flying around above the coordinating altitude in a low threat environment and thats the only time a MAGTF would be on its own. All your doing in between the boat and the RP is flying in formation with a Tiltrotor.
We have a radar, it doesnt do shit for your weather capability. If you cant see you cant see be it with FLIR or NVG. They arent going to shoot if they cant see so putting them in the air to make rotor noise is what idiot ground commanders do because "Its my asset and I want it" type attitude.
Cant Fly high... show me any time you've had troops above 14000 feet. Thats pretty much the limit for altitude on where rotor guns can support.
Loiter time. Rotory is typically longer than Fixed wing. Ill go 2 hour in the stack while Vipers and A-10s are yo-yo'ing after 20 minutes. If you want constant coverage during FARP turn arounds thats as easy as tasking teams to do battle handovers.
Threat. CMWS works, extremely well by the way. And Hellfire gives you more than enough standoff for any kind of light AAA. The helicopters that get shot at the most and take the most fire are down at 300-500 AGL because they have to be not because its tactically superior as a tactic. There are plenty of ways to mitigate risk.