but fire eaters take a LONG TIME to charge up.
Point taken. Leave them out.
Meh. Colossal Dragons seem like such a waste; 10
for 7 damage? That's not cool. I guess you could use Mercenaries; upgraded, they're 2
for 3 damage, which is nice.
So:
I'd switch 5 X Colossal Dragon and 3 X Gravity Pillar for 5 X Graviton Mercenary and 3 X Momentum.