I'll have to agree on the file size and I can say that it sucks - coming from me, yes! And I understand why most people are getting set off on even trying it when I myself had my own issues with it, not to mention with Blizzard and the way they do things now, yes I am not kissing any of ther arses! They do both good and wrong so it's a 50\50.
They set that limit on map size for performance reasons, any bigger and your performance might suffer, as for the other limitations they added, it's ridiculous, especially for multiplayer although it's way better than wc3 but You'll have to keep in mind that a sc2 map files the file size a lot faster (let's say only custom terrain textures can easily be 20mb (if you are working with sc2 standards), the rest is a lot more). I personally don't care about the multiplayer, a single player mod is satisfactory for me, and there are no limitations, not even mapsize since it can be placed in mods.
A way around the map size is to scale everything really small, even the tiles can be scaled to match the units so that they look good at close up. The only problems will be with the shadows which will look weird on the scale but still work fine. A way around eve this would be to use static shadows if you know what you're doing!
I am starting to think people also don't give it a shot because it's more complicated than wc3, and it is but that is a price to pay for all that stuff it does.
