The biggest thing they could do for Bulwark is reduce the CD time to match Awareness to increase synergy and compatibility. Awareness is a Pld move, after all, but Pld's get the lowest utility out of it because it does not pair well with Bulwark. An increased in Bulwark's duration would be nice too, but not required.

I do think it would be interesting if Shelltron's CD followed the same reset rules as Drk's Low Blow, though. I feel like this kind of adjustment would make the shield feel like a more vital part of Pld defense (which it should be) because their block rates would go up substantially.