I am not sure that tomato control and Dark World really mix so well. I mean if you are going to run Tomato you might as well run the Scout of Dark World, and he isn't worth it.

I would thin out your monster line up by 3 or 4 cards and add a second Dark Deal (because it allows for the activation of the Dark World monsters' second effects as well as activating Despair from the Dark's special summon effect as well as a few other monster's effects when discarded from hand by an effect controlled by your opponent).

Also, without Tomatoes, Creature Swap isn't worth using for only 1 monster (Morphing Jar). I would replace 1 Creature Swap with a Metamorphosis.

The summary:

-2 Tomatoes
-2 Newdoria
-1 Dark Jeroid
-2 Creature Swap

+1 Monster Grizzly
+1 Metamorphosis
+1 Gateway to Dark World
+1 Dark Deal

By the way, with Metamorphosis you now have access to these monsters:
Treeborn -> TER
Goldd/Sillva -> Dark Balter the Terrible, Fiend Skull Dragon, or Reaper on the Nightmare.