I'm going to try Teebo leader soon, just got him max gear, ability and 4*. He has 12,315 health right now. Going to take out Sid I think.
My thoughts are his random stealth on defense may help win a decent amount (20% +) on defense. Probably take out Sid. My thoughts are it will help for lumi to be able to get her heal off so offense can't single out toons and kill them immediately. Will also have RG to 4* soon.
However don't think I want to waste purples on him or farm his gear to take him from gear 7 to gear 8.
Although logic tells me this is all a pipe dream since no one runs Teebo at leader and you never see anything on the forum about it being viable for a defensive strategy.