B) the factory 280 Rem out there is loaded to lower pressure than similar cartridges (25-06 & 270), but hand-loaded 280 Rem gets close enought to AI velocities when loaded to like-pressures
C) 280 Rem factory ammo is nearly as difficult to find as 280 AI
D) there are different versions of the 280 AI and Nosler brass doesn't work in them all, while 280 Rem factory will fireform in all chambers
I think they're both fantastic cartridges but don't think you'll be able to tell a difference between them recoil-wise.
The only thing that needed improving in the 280 Rem was SAAMI pressure specs. Otherwise it's superfluous to AI it.
