Have you playtested against other common Legacy archetypes? What are you having trouble with? What is happening that is bad?
As far as your early game and looking for 2-3 drops I'd recommend any RR or RRR creatures with haste and adding Nykthos, Shrine to Nyx to help with a consistent ramp factor. Guys like Ash Zealot can put pressure on or at least draw their removal and hate while you setup to drop your bombs.
None of your bombs have haste nor do they have a way to get haste leaves them open to sorcery speed wipes and removal. Which in terms of card advantage is a two for 1. You cast geosurge to cast Balefire, then pass turn. Doomblade is a two for one, possibly on your turn. That's a problem.