I had the chance to play a tf2 center on this and although the map is seriously aesthetically pleasing, in terms of gameplay, I would say I had a few issues with it
I can't say much for 2nd or last, it's not an organised game and there didn't seem to be anything particularly wrong with any of that, which is nice. And I really like the dropdown onto 2nd which allows for a fast push if they failed a last push, I think that's well executed, and I like the relatively neutral high ground on last.
But the mid is unfortunately really flawed. When you play the mid, it seems the best way to play is to just sit up top and spam the whole time, because from there you can see everywhere and it's very safe, the height advantage is far too significant for the side routes to do anything relevant, especially since you can see into it, and to top it off there's also a medium health pack. If you're stood there and the other team actually attacks you, you would have to seriously fuck it up in order to lose the mid
Actually it happens that if you sit up top it's also impossible to really attack aswell. If you're holding forwards then you have height ad and a health pack, and coming through the top you have an extreme choke which isn't going to go well if you try to uber through there, you're gonna get stuck against explosions you cannot move around and have a terrible uber.
Sitting far back on mid, the same thing basically happens as it does on mid. If you have equal ubers the first team to aggro will lose, but you have the added negative of you have to eventually aggro or they just keep getting forwards and then you just lose.
If the defenders have a sniper on the far back area, it sees literally every entrance except the one at the bottom which you can't push unless you have a deathwish. This is a serious problem because you're way too far away to do anything, you're forced massively early, you can barely get to the upper area with a sticky jump and I don't see how you would ever get in.
Not to mention if you do get to push them out, you end up putting a scout on the cap which is so far down he becomes completely irrelevant which maybe allows the enemy to repush if they'd have ad now.
So my solution to these problems would be as follows:-
I would redesign the flank routes so that you can potentially get behind without being spotted, so for me that'd be widening it and making a pillar that blocked vision to the upper area. I would remove the health from up top, there's no need for it, and I'd add hp to top off point. That way after the soldier is denied trying to get up there, he can at least get a meaningful rocket off, and he can jump again after taking health. I think this would make the mid fights a lot less grindy. I have no idea what I would do about the sniping problem, this is one of the struggles when you make a I-shaped map instead of an S-shaped map :-(
PS, you can hide stickies in the upper area pillars on mid, which imo is a big problem