I think this is a great Romeroesque map, with a few reservations. My biggest one is the Southwest corner of the map, with two rooms (the curvy rock in lava and the U-Turn with cages and jumps into dark lava) are too close to their abandoned mines counterparts. For me, they snapped me out of an otherwise engrossing map. The S-curve rock I think would work if you took out the cacos/pain elemental - another Mancubus or a revenant would change the feel of the room sufficiently, and would echo Romero's placement of sniper monsters elsewhere. The U-Turn cage I think needs a new gimmick (a few ideas below).
My other focus would be the map slot. Due to both the structural parallels and the difficulty, I think this would have to run in the Map29 slot. In fact, I think it works better - the vast bridge to the final Cyberdemon feels like an ominous gate guardian, and the whole level seems like it's balanced to be just a *bit* harder than Living End.
As far as play notes/likes/dislikes:
+ The revenant warping in at the start was a very cool surprise on top of the chaingunners. I think you nailed the whole starting section here: a quiet start that quickly turns ugly, with a down lift thrown in. My favorite from your Romero maps. The visual of the two towers out the window/lift really works as well - visual impression was always a huge part of Romero's designs, especially at the start.
+ The revenants/baron combo on the tall ledge a little later works really well, especially given a clear goal behind them. The hidden lift from the area where you first see them is a great double secret.
+ Given the bridge at the end, I think the Cyberdemon should be placed slightly back. Chances are good he'll kill the player at least once, but more distance gives a precious second or two to cross before it blocks the bridge.
+ It's a bit abrupt how you get the green armor at the start, and the blue armor in the next major room. Romero rarely did that, spacing the powerups out as a general rule. The SSG does it right here - you've used the normal one long enough that you want it bad by the time you get to it. I think with a bit of balance tweaking, the blue armor could reasonably be moved to the bottom of the S-Curve room.
+ As far as the U-Turn cage room, I think the main issue is that it uses the same idea as abandoned mines. Comparatively, Industrial Zone did the same, but with Imps around it at closer quarters and no way outside from the middle. A similar structure but with a different fight (perhaps 2 arachnotrons with good crossfire angles, and more open/less walled) would let you keep the iconic pattern without feeling so much like an homage. Alternately, if there were a second path it would feel like a different design, a blend of the icon room with winding branches used in Maps 15 and 17 wood areas and Map29 marble.
+ If this were on Map 29, perhaps "The Crossing" would be a more fitting name, evocative of the border between life and death the way Spirit World was in Doom 2?