Medieval theme always runs the risk of being way too brown, but it doesn't have to. Throw in some nice green grass or something! I know it's alpha, but if you've started texturing, should texture interestingly.
Also, the map looks quite small from the screenshots. while it's hard to tell the scale from static images, I can see on the overhead that there's a platform that overlooks the spawn on one side and the control point on the other, which could be too powerful as the red team doesn't have to move to defend the point. If you look at all the official maps, they have a powerful spot at the start of the map that the robots eventually overwhelm, at which point the red team's forced to retreat, normally to the cap - that's where things get interesting, they have to stick together in the chaos, try and push back, etc.