Yes, the NSA could still get your metadata, content from your ISP with an NSL, but this would eliminate the possibility of getting your email directly from the g00g
The one advantage I see is that someone has to write the NSL in the first place so if you use a hosting provider that is very small you'd probably avoid attention just due to prioritization of resources. But that would only last until enough other people become aware of that refuge for it to become visible on the NSA's radar...