Also, I would definitely keep the Primordial Hydra in, and leave out the Predator Ooze. Yea, the ooze is indestructible, but it's still prone to anything that exiles a creature, or gives it -X/-X, and the ooze grows way slower than the hydra. Primordial Hydra cast with 4 mana = an 8/8 next turn with the Corpsejack out, and the following turn a 24/24 trample! The ooze would be only 5/5 at that point! Just sayin.

Nice! I'm working on a similar BUG concept, but I went heavier into black removal to buy time. I recommend AEtherize and Ultimate Price. Otherwise you'll get run over by aggro decks before hydra does anything exciting.

My list is Life and Death in Ravnica

Also perhaps Arbor Elf instead of Scorned Villager  ^Flip? That curves better with Somberwald Sage for turns 1 and 2.

I have Scorned Villager  ^Flip in there for a few reasons. I know Arbor Elf is a 1 drop, and can help bring out Somberwald Sage turn 2, but, Moonscarred Werewolf  ^Flip is a 2/2 so isn't quite a dorky, and the vigilance aspect allows me to attack and then tap for 2 mana, which I like.

But who know's Arbor Elf probably play's better with the shocklands.

Mine has more control to help delay the game to turns 6 or 8. Aggro has to be dealt with, there is no way you will be faster. (Sure, you can reach 20 damage on turn 5 and 100 on turn 6, but that doesn't help much if they hit 20 on turn 4)

The main concern here is that you really don't need 4 Primordial Hydra to get a kill.

Main deck AEtherize and maybe add Dreg Mangler ? Maybe lose one each of Essence Harvest and Sheltering Word to main deck 2 or 3 Vampire Nighthawk ?

I love Necropolis Regent but I can't think of a good match to sideboard her in. maybe fill that slot with the Predator Ooze to help against control.

Jarad's Orders doesn't seem that good, although I see its purpose. Maybe replace it with another threat that you would like to see instead of using it to get the hydra? I'm considering Nimbus Swimmer for mine but I'm not sold yet. Works great with Corpsejack Menace