Well since Brock and Kurt most probably. Kurt having the triple crown within like 10 months will probably not be beaten though, especially given it was an era where Austin, Rock, HHH, Jericho, ****** and Mick were at some point if not all of it full time. Forget the likes of Edge, Eddie, Taker all being there too.
But yeah, they all worked well in that 99-03 because they were pushed aggressively and quickly into spotlights, it worked amazingly with the Shield over the past few years, they need to do it again. Doesn't mean you have to hand them the titles quick, just give them spotlight that means something, so that when they go down in the card, THEY mean something.