The problem with utility cards are that fights are designed to be possible with 0 tenacity, a tanks own cooldowns, base movement speed and your own mana pool. If your team are playing reasonably well, most utility cards are unnecessary. You have the fight mapped to beat it without them. They only feel useful. On the other hand, dps is always useful.

Having utility cooldowns on back-up incase of someone messing up is nice, but the game just doesn't support making a full rng based system out of it. Especially when some cards are better and compete with the situational unnecessary ones.

If cards are going to be utility, they should probably be something separate to the dps cards entirely, rather than instead of them.