Yea, that option does rely a lot upon the balance of the cards produced and a lot of playtesting.
Alternatively, you could consider allowing players to discard a card from hand (or in this case, using an ability for no effect) in order to provide some kind of bonus defensively. For example, use an ability for no effect to get +1 defense, 2 abilities for +2 etc. In this way they can avoid taking damage but their opponent still gets a benefit from having raised their dexterity massively.