Glad you liked it! I'll definitely agree that the forced return to the glory hole are a little flat: there are many experiments here, and not all of them work. I assume MOST people probably only did that route as a secondary anyway though, or had an earlier save before getting addicted, so it wasn't the end of the world.
But yes, Mezz is DEFINITELY aware he's desirable. Or...well it's complicated. He's smug about everything, including that. But I think he's one of those people who's laser-focused on a particular thing, in this case being the image in his mind of what a "hero" is. He's not SO laser focused that it makes him an asshole, he still cares about and helps other people, and not just to stroke his own ego or live out his own self-image. But it does make him a little blind to other things, like how Scratch feels about him, or maybe even the thugs he encounters.
In his mind, I think he sees all those interactions through the lens of "bad guys torturing the hero", or in the case of say the center path, the hero doing something sly to sneak past. Mezz I think is one of those infuriating people who's very good at what he does, but never really takes things fully seriously until he's FORCED to (which he obviously is, quite frequently in these games). Again, not to the point of being an asshole or being shitty to people, or being totally divorced from reality: He's still somewhat practical, down to earth, helps people when they need it. But he definitely has an ego, and VERY much enjoys what he does, and gets kind of caught up in it all. Which is why it's so much fun to pull him forcefully out of that.