The current system could be improved, but I'd rather not go back to EW cards. Damage is always useful, but I like variety and having cards that don't need to be played immediately most of the time.

Having multiple mitigation options isn't a bad thing. It could even be argued to be a good thing because it means there is the potential to combine different mitigation tools to increase effectiveness which can be more interesting that just having a dedicated single use button for it that's always the same. SE could probably lean on this more and make the support cards have more of an augmentation effect on other skills, though the main problem remains the undertuned damage of most content.