Because not everyone can carry AJ Hair Styles on the mic and in a promo like Jericho did. Eventually, like right now, he is going to go into programs with other guys that can't work a mic or a promo. Fans like myself like good promo battles and the hype and build it brings to a match. Flame away at "fans like myself" for enjoying wrestlers who can cut good promos and who have good charisma but we are out there in huge numbers.
We like AJ and respect him but we also want more because we have low attention spans. I have no interest in this AJ/Reigns match. These two together can't build a bigger story that captivates me because neither can sell me on promos. The story behind this match is one the smark fans created because they don't like Reigns and it's trendy to boo him and they love AJ because he is AJ. That's not a story line between two guys in wrestling that's a story line of the fans and it's getting boring.
I'll ask the opposite what would it hurt AJ to be in a stable again that can hide some of his flaws and make him even better? And who said anything about that stable having to be heel? I only mentioned the Bullet Club because it's the easy to go to example right now. Any spin off of it, if they it down the road, would be a face stable anyways if AJ were to join it. I will agree a stable doesn't have to be built now but down the road I think it needs to be done.
I'm not mortally against AJ being in a heel stable, if there's going to be a Bullet Club reformation, or whatever, but his face run has to run its course first. And there's really a lot of reasons for it:
1) He is over.
2) He is main eventing shows because people want to see him.
3) He is selling a ton of merch (since people want to see him).
4) He is putting on great matches.
5) The company can't get their #1 face over, and are in desperate need of a face who is. And from most accounts they are surprised by how over AJ is. Vince is too out of touch to know who and who is not over when it comes to guys who aren't on the roster.
6) There's frankly not enough credible heels (left) for him to be in a faction with.