No one should "split" from The Shield... They all should. The group began and continued as a unit unlike anything we see anymore or ever. The group should gloriously self-implode, not fragment and splinter. Or much worse, replace a member.
Anyway, I can't wait to see what Reigns and Ambrose will do while Rollins I'm still undecided. The Shield was brilliant and the group doesn't actually need to end yet but the wheels are getting wobbly. I noticed them teasing it on Raw too, Roman gave Dean looks during his promo and then won the tag match by taking care of business himself. If The Shield are done I think Reigns is the most likely to excel at this point anyway.