i appreciate the amount of detail you've put into this post! a lot of the weird, little inconsistencies were due to time constraints. since this mod was made in a month and i worked on it until the last day i had, not all of the issues with the mod have been solved. as well as this, i really feel like i didn't flesh out and use most of the enemies to their full potential, and so i think some enemies are a little overrepresented, like the spellcaster enemy you mentioned, and others that are underrepresented, like the hellknight statue or the machinegun cultists.
originally, the revolver was going to be your first weapon before i decided against it. the slow firing speed made it unfun to use, so i went on to make the pistol instead. the truth is that i didn't really balance it as well as i should, and i do agree the revolver could either be buffed or made to shoot faster. the original idea for it was that, by design, you're not really meant to use it after you get the shotgun, since it's a weapon i wasn't sure how to implement in the balance; honestly it's just not well balanced, and in retrospect, i'd change it.
some of the weapon quirks were on purpose (i like the fact the shotgun always dispenses a casing, it was supposed to be akin to the shotgun in COD MW1). in retrospect though, i think my decision to change the magazine size on the m16 to be 50 was due to some criticisms of naku-naru's weapons, being you'd have to reload so quickly that it made using some of the weapons less fun than they could be in that mod, and making sure the same couldn't be said of the m16 in this. this really wasn't a good concern to try to address i think in this because it's designed differently enough to the original doom this becomes a problem. looking at it now, i'd probably lower the magazine count a bit since it really made the m16 become the workhorse weapon over the shotgun, which i don't think makes it balanced since the idea is to use them both equally for different encounters.
as for that strange map glitch in level 2, i'm still not really sure what causes that in the architecture. there must be some conflicting lines there to cause that.
i think, at some point in time, i'd like to patch and maybe expand the mod a little. i don't currently have the intent to add any new levels (really, i feel like dead men tell no tales works as a short game because it's a short story), but i'd like to fix a lot of these little issues the mod has.