I'd like to see a change to combat expertise - firstly, give it's current benefits to defensive fighting instead so the tanks don't lose anything (drop the increased spell cooldowns though, or at least reduce it to 2x & casters could have a handy way of getting a bit better defense.) & then turn it into an imbue. This imbue would be somewhat different from the others, not giving a direct damage boost but instead have it grant a stacking +2 bonus to all tactical DCs per die. I think it'd be a fun way to improve many types of characters' combat options beyond just relying on pure DPS output.