Ability delay and the weapon swap delay; those two things cause more frustration and player character deaths than anything else. I'm certain of it.
Please fix this asap. As a Templar tank, I am constantly swapping to 2nd bar and back as it's a crucial part of my build/survivability.
I hope it's something you are working on a solution for. If any one thing kills this game, this will be one of the prime suspects.
No matter how interesting the lore, or innovative the design, if the combat is clunky and unresponsive people will leave. Period.