I'd remove Awe for the Guilds, Elixir of Immortality, Staff of the Flame Magus, the Pillar of Flames, the Shivan Dragon, and maybe replace the Legion Loyalists with something better.


Trample and First Strike might not be that useful since most of your creatures are flying which will bypass most blockers. I'd put in 3 Shocks instead of the Pillar of Flames and a Balefire Dragon to replace the Shivan Dragon.


You can also reconsider Strionic Resonator, but it might pair well with the Slumbering Dragons like you said. Having just one would make the strategy pretty incosistent though. Maybe replace it with something to generate mana? You would definitely benefit from it. See Palladium Myr, Iron Myr, or just stick with 4 Darksteel Ingots.


You can use Furnace Whelp for a 4-drop, but you might want to use something else, not necessarily a dragon. A Palladium Myr could take the spot too.