I think some of the current issues with deckbuilding, combat and that you are forced to make small limited decks because you have to guard against certain skillscould be resolved if you could dedidate your 5 buttons to either defense, offense or utility.
So here is an example. Of the 5 slots which are currently random you could make 2 defense, 2 offense and 1 utility. In in those slots only skills of that category can pop up after you used them. Also it would be cool if you could dedicate the slots to certain skill categories aswell. For example an archer would be able to pack 2 defensive slots and maybe 3 utility(we would need more utility skills for this) which would allow him to support from the backline.
I believe, that this would enable you to build more versatile decks while making deckbuilding and actually picking the right skills more important. This would also allow for more situational skills like for example steal thunder to be actually used.