How about Archangels instead of Dragons? Less init HP, but healing
They'll also come out faster, which with Overdrive will get them doing similar damage anyway. Ie:
- Angel on turn two, overdrive on turn 3: 7 + 10 damage, increasing by 3...
- Dragon on turn 3 + overdrive 15 damage, increasing by 3...
*Edit* it also let's you squeeze out a few pillars, possibly for momentum.