Metal around A : move the existing stacks to more obvious spots (especially that big box), add one or two additional medium boxes between the point and BLU's spawn. General area around A could be a little overscaled / too open.
B was alright with me in terms of layout and scaling, but I think BLU's spawn times are too long. For A/D maps Valve's spawn times are 2s for BLU and 10s (default) for RED, and I think you're a little far from that. The final room could be a little biger as was mentioned (plus big, impressive final rooms give a sense of grandeur to your spytech base), but make sure that there are at least one or two sentry spots that can cover the capture area and can't be easily outranged from anywhere the attackers are coming, the wrangler shouldn't be a requirement.