Melee maps don't take as much time to make. As Rose.Of.Dream said, certain maps take longer than others. Nostalgia took 8 hours(in all) to make, but another tourney map only took 1. Melee maps are hard to balance and give players room to make interesting plays, use different strategies, and make good replays for others to watch. UMS might take a very long time to make but it could be considered easier since the terrain doesn't matter. How well you map is depends on your triggering skill and, well, how fun it is.
Now about the map, you might have a bit too many mins in the middle. If you have, like, over 12 or some mins in one location, people could consider it a BGH map, unless the map is really made well and the loads of mins are balanced out. I've seen a game where there were, like, LOTs of min patches in the middle but it was a pro map, and a very good one at it too. And it's hard to tell since the SS is so small but it looks like sort of an island map, with all the expos at islands. If that was your intention, then alright, but if you want a regular melee map you could make ramps connecting to the islands in the middle.
P.S: Use this program to take larger SS'.
http://www.staredit.net/index.php?download=173