Yeah full passive immunity is pretty strong you're probably right about a cooldown on it. The sprint delay is certainly a neat idea I hadn't considered and I'd happily swap it out for the move speed & slide distance although I'm partial to keeping the sound distance thing is because I think it's kind of funny

(I know this isn't good design but still).
I'm curious about the Health Regen to Out of Combat Regen. I don't think it would be too strong and there are already a lot of more sources of OOCR then HR.