Fix paladin. Only Class in the entire game that cannot...

[Reynhart]

Gameplay wise I think that paladin should have been the support tank - focused on party buffing.

For me, as a "Main tank" it should have focused its survival on healing, being the only tank that requires knowledge in magic, and as an "Off tank", on covering people in time of need.
Two things that are severely downplayed.

A blunt idea that could have been interesting is allowing Rampart and Sentinel to be used on a target. Maybe the enhanced version would only apply when used on you, to not be too powerful. And Cover made into a trait triggered by critical HP and proximity.