Yeah, the map is huge. The middle point is pretty good, but the fourth one is too big for its own good; it's wide and open, meaning a few Snipers or a single Sentry can hold the fort really well. It's also high, vertically, which means you have to actively work upwards to get at it, and, well, typically when height variation is involved, the team with the higher ground tends to win out (in this case, the team defending the point). It had a tendency to stalemate.
Somehow fix that much, though, and I think the map will be quite good.