Didn't really feel too big to me, less big would be cramped and prone to spam. There's a fair bit of walking when attacking B, especially as a slower class, at some point I wished we had the forward spawn after capping A. Having at least one offensive engineer seems compulsory for the teleporter but overall that's probably alright.
Many flanking routes, I'm not sure they're all needed. The layout can be disorienting due to the theme, but signs seemed to be sufficient, I was never lost for more than a few seconds.
The gameday was underpopulated though, that much is clear, and it seems that teams were fairly imbalanced as well, so overall not ideal testing conditions..