A 24” barrel is great at the range but not so handy otherwise. The current trend has been towards shorter barrels and collapsible stocks. It makes a handier platform but it also ends up robbing velocity from the 5.56mm cartridge which is very much dependent on velocity for its lethality. So, what we need is a way to improve the terminal effects in the short barreled ar15s and there are a number of ways to do that but the 22 Nosler may, IMO, be the most reasonable way to accomplish this task. It’s typical to poo poo new cartridges even when they are superior to the cartridges they seek to supplant. We have our reasons for this, brass/ammo availability for example;however, no anount of poo pooing changes the fact that the rounds are, in fact, superior. Personally, I have always liked the idea of a 22-250 AR but offerings were quite limited so I see this round as being a useful round. It fills that niche nicely- perfectly even. And, as yiu said, it can be necked up to accommodate, for example, 6.5mm projectiles which would also be very interesting.
"Superior", in reference to firearm cartridges, entails a lot more than just theory and paper ballistic data (and the ever-present "ideal" marketing hype). The 22 Nosler accomplished those modest improvements to velocity thru cartridge design and longer barrels as I read it. And we agree that .22 bullets are speed dependent for their performance (speed kills). The heavy 22's have poor terminal performance and the light 22's with their velocity shedding BC's get too squirrelly at any substantial range. I've popped a lotta groundhogs with VMax's at medium ranges (close-600ish) with light-medium 22's out of 22-250's. They're ok. Close was more "exciting", tho'. And yer gonna hafta watch for thin jacketed bullets spinning apart with that velocity increase in that fast twist meant for heavier jacketed bullet types.
It's prolly just me, but in my old age I like some substantial gain and an absence of PITA if I'm gonna have another rig. Unless I get caught with the hot-runnin-wants after somethin'. Which does happen occasionally to us all. Poor slobs. I will admit, the "mini-.284" concept gave me a l'il pudgy. And yup, I'd bet it'll be 6.5'd in short order. Too bad about those 6.8 mags, tho'.
My personal fix for the AR Blues was a SCAR17s. We're still honey-mooning after a coupla years and yes, I had the hot-runnin-wants for somethin totally not necessary! Hehehe. d;^)