The Terran Advantage

I like the Baneling/Mutalisk approach. Speedlings and Banelings and Mutalisks can rock Terran. Of course I don't try to engage them in a one-on-one fight until I have to. If he leaves his base, Banelings can take the front door right off it. Not to mention Mutalisks can jump caverns. I think Speedlings/Banelings/Mutalisks is your best bet vs Terran (sometimes).

Forcing him to go outside of his way to get extra units is good out of the box thinking ^^.

As far as having trouble with Medivac drops goes, I don't see how this could be a large issue. Put a Spine and a Spore behind your mineral line, I don't think you need to leave any burrowed troops there. A Baneling or a bunch might be a nice surprise though. By the time his units set foot on the ground your Speedlings/Baneling/Mutalisk army should be almost there, no?

I mean the Zerg army is fast, not to mention on Creep, so I don't think you have anything to fear from Medivac drops Maybe cliffs..