I think that he should look more on the Draw strength in the deck, because I would use tinge of Green, as I did and would use
Opportunity and Urban Revolution to draw cards,
Vapor Snag for unsummoning his creatures,
Rancor,
Simic Charm and
Drakewing Krasis.
This is what I did with Drakes:
GodrakesI don't wanna point it out as an exemple, but from Modern decks here in Deckstats it has the biggest score as a Drake deck.
So I am a bit proud of it, but the protectors are shit and I don't play it very much. Nevertheless in game it is very menacing. However from siding out the Drake deck and the Dragon-Goblin deck:
Dragons and Goblins Horde, at midgame the Dragons are a bit bigger than the Drakes. And there is no Planesewalker to relate to them as Sarkhan can do it in black-red, green-red, blue-red or mono red Dragon deck.