Ok, I had a runaround and found some stuff:
* No spectator cams. Put these in, otherwise people end up looking at the bottom of the map
* Stairs not playerclipped (in dev, I'd just use ramps - they're smooth by default and they're a lot quicker to make/remake) (same goes for doorframes - they're awesome and they're really useful to keep door sizes sane, but you will be moving and removing stuff a lot a lot in alpha)
* Holy hell this sightline:
http://imgur.com/qVT32S7
* This is pretty dark. Might play well, might need fixing (but I'd turn up the lights in that room anyway):
http://imgur.com/67QySjC
* No signs
Also, this could be extended:
http://imgur.com/5DvahNd and
http://imgur.com/CoBGHL6
Generally, you want stairs to be a 2:3 ratio, not 1:1 (most people use 8 tall and 12 wide, afaik):
http://imgur.com/Ci1TXVy
SIGHTLINE!
http://imgur.com/RsECOfy and
http://imgur.com/Ixq8ITv
Besides sightlines, you might wanna move a few buildings because atm it feels like you're either in a building or cramped between two. Look at other koth maps - they all have significant open gameplay spaces. Try deleting a few, see if that helps