Courage of the Collosus is OP but ... if only the other resolve tree keystones were good,
personally i would say to get rid of the flat base alltogether. that's 190 shield less at lvl 18
but its also the first viable tank keystone i feel has good interaction from a gameplay perspective. big impact shield with the longest Cooldown out of all the keystones and lets not forget the shield lasts for 4 seconds and 1-2 seconds of that your target wont be doing damage anyway because you stunned/knocked em away.
I just wish riot would take a look at undying grasp and Bond of stone. they feel pathetic compared to any other keystone out there.
, which has better reduction stats, heals you, and also comes with some decent base stats. Only downside is that it only affects 1 person.
and
with 