First, let me say that for a first map this is pretty great. The detailing looks nicely TF2-styled, and while I haven't played the map and therefore can't comment on the gameplay, it's nowhere near as blatantly broken as basically all first maps are. It's certainly leagues ahead of my first map, and it may or may not be better than my current efforts. Those things being said, here's some negative stuff.
You really need to stop doing this. I know I used to do this. I hope I've stopped doing it. I totally recognize how you're thinking.
You've planned your map carefully. Someone questions your design choices, you respond by stating why you made these choices. Here's the thing, though: no matter how good your intellectual reasoning is, an instinctive 'this feels wrong' from an outside perspective basically always trumps it. Like when you say that the map really isn't a maze; the layout makes perfect sense to you because you've spent a bunch of time in Hammer constructing it from scratch, but if someone else who plays the map says it feels like a maze there's a decent chance that a lot of people who'll play the map in the future will think it feels like a maze, and that in turn is a really good sign that you need to make your layout simpler and clearer.
Also, what does the 'I hope you understand that the layout is in no way final..' thing mean? We all know the map is a work in progress. That's why we're giving you feedback.
On a completely different note, don't detail your map prematurely. Start out building your map out of devtextured base geometry, and keep it that way through all the alpha stages. Only when (if) your layout ever gets perfected should you proceed to the beta stages and start putting in the esthetic stuff. Redesigning your layout is much easier when you don't have a bunch of visual crap to delete and rebuild every time.
I'm tired as hell and pretty drunk. Hope I'm making sense anyway. Good luck!
I admit my reply to Forty-Two was kinda rushed and not very well thought out (I was typing it on a cell phone) but I just wanted to clarify that I wasn't just throwing stuff together randomly. But I did actually take a lot of feedback from him (and others who've said pretty much the same thing) and I have used it to improve the latest versions of my map. (Keep in mind that he made that post when the map was only in A2)
For example, the ceilings are a bit higher now and the interiors feel a lot less maze-y in my opinion. I try to get the map into as many impromptus and gamedays as possible to see if others think so as well and so far people have been pretty happy with the layout changes, at least I'm not getting as much negative criticism about the layout anymore.
About the detailing, I knew pretty much since I started making the map that everyone always says not to detail the map from the start, but since it's my first map I found it hard to make it look as I'd imagined without giving it the proper textures and props so I decided to do it anyway despite knowing I'd get a lot of shit for it.
Honestly though, it's turned out pretty well so far as I feel I can make significant changes without any major hindrances. I will definitely consider not detailing my alphas in the future, though.