C is a tricky area.
The cap time is long (for good reasons), but it's always incredibly protected, even at it's lowered state.
As an attacker you can see the enemies coming (while capping) trough the glass, but can't do anything about it. You have to peacefully wait until they decide to pop around the corner, and at very short range.
Now, This makes it so you have to practically dominate the entire C area to succesfully capture it. Not a bad thing in itself, but in combination with the layout that mostly favours red It can feel pretty tough as a blue player.
I think you can make the last capture a little more vulnerable to attacks, so that the fighting is always about the point, and not about going berserk on the spawndoors.
I've not played enough to say this is good advice, but It's my inital reactions.
Also the sniper windows at C are overpowered. Force the snipers into a more vulnerable position (where they can be shot at with grenades/rockets), as it is, that line provides too much overview with very little danger.