Unlocking all the second tier classes was assumed, since they don't come with glyphs. Not unlocking the Witch was also assumed. I also disagree that you need to unlock GG and TT for the monster classes.
For Half-Dragon, you want GG anyway so you just have to give up TT. There isn't a lot of room to regen fight the final boss, so the poison isn't as critical. All you need is another deity to convert to so you can use your potions. Besides, I'm 100% sure I got all 3 of my wins without TT in the first place.
For Gorgon, you get GG and TT anyway in Naga City. Since you have the Agnostic's Collar, you can still grab what you need.
As for the Vampire, I've beaten his dungeon Purist. I'm not worried about deity selection
I wonder if unlocking a monster also unlocks its boss equivalent? If that's the case, I'd say unlocking Sorcerer is actually a mistake. Not having to fight Bleaty makes things even more consistent.
As for needing GG to unlock Dracul, is that confirmed? I've seen just about everyone else in my current game, so I'd be surprised if that was actually the case.