New Pantheon: Riot, why the damage immunity on his new E?

From what I've watched so far, on youtube, Pantheon's rework seems really good, fun to play and definitely more skill based than his older self (although, not by that much).

But I've noticed that his new E ability has complete damage immunity for the complete duration of his channel (1.5 sec, or 2.5 sec if empowered by his new passive) while he's still doing decent damage, as well. This blocks turret damage too, which is pretty busted!

Why, though?! Why not give him increasingly X% damage reduction per rank, instead?! Like 's E. It doesn't take a genius to understand that this new ability is gonna be OP and a pain to deal with.

New is the son of and , confirmed! The new E is Kinda like Braum's E + Fiora's W combined with pantheon's old E.

Also, I think that the CD on this new E should be a bit higher, since I've noticed it became easily spammable by rank 4 and 5, especially with CDR items, which Pantheon will definitely build (at least and ) and with runes, the 45% CDR on him is gonna be disgusting!

Maybe also give him a self slow when he's channeling E?! Although, this might be a big nerf, if Riot is planning on leaving the immunity on the ability, I think it's a fair limitation to have on the spell.

Otherwise, the rest of his kit seems fine to me, and the numbers seems ok, for now.