Dunno if anyone else heard, but Blizzard confirmed in their most recent Starcraft developer update, that they will be eventually removing the sprite limit that currently exists. For those that don't know, this is the dreaded "cannot create more units" map max bullshit that keeps things like dark swarm from working, or basically building anything. They didn't announce a date yet, just said it's coming. This isn't usually as much of an issue in 1v1 but it definitely can be in 2's / 3's.