It looks like a
very good map now, but it still has a
little bit of room to get better
since you asked for more sugguestions, here they are
1. try to fit in some lower-levelled terrain at the bottom mid,
this makes it a more tactical area and makes it a little easier to defend
2. reduce the minerals in the starting bases, they are
way too rich in resources, reducing the need to expand
3. the middle base needs less minerals and better placed gas (it's too far from base area,
discouraging zerg from building in it)
4. the top mid is a little too big, it should probably either be smaller or more decorated
ADDITION: It looks like you can't build in most the expansion bases, but it might be because of the small screenshot.
You probably need to test the expansions and the mid right base, and fix them if it's messed up