Took me awhile to get my head around it but I'm there now (coffee needed
) - I like the idea of the SCU behind the spawn point but it looks like one big choke point. The fast tunnels don't really alleviate the problem (both currently and in this design) as they look to still be camped by a couple of people and effectively made redundant. Equally with one entrance to the "main room" this is easily locked into a stalemate by the defenders camping it (unless I'm reading it wrong?).
To my eyes it looks a little too linear and needs pushing out more to the sides.