Yea, I tried to adding direct heals however, the time required to draw them combined with the small amount of heal combined with the high cost made them very inefficient.
It seems I made a drastic flaw in my logic. I assumed that gem slots where there to help you diversify if you wanted to but according to the boss they are there to screw with you as you level up
I don't know anything about pokemon cards I however can relate to your card reference and I can tell you I had a pretty sweet hand every time with my first 9 gems. Things I could kill at level 9. I can no longer kill at level 11 and its all due to those 2 extra slots.