Sorry, more Arcane Tower updates that I feel would help encourage more player activity here.
Right now, broom closets rooms can only be bought by:
Wizard
Sorcerer
Bard
Elementalist
Spellsword
However, the Tower Code has nothing against hemomancers, and even has a statute allowing animation in self-defense [if there are no other measures]. Hemomancy is still a good step away from undead. The Tower Code also purports itself as neutral, so it shouldn't be so finicky about blood magic. Lastly, it has a DM-insert NPC that has multiple pacts. I think hemomancers should be allowed to rent here. That DM insert may as well be an argument for warlocks, too, but I won't push my luck.
I also believe rent should be opened to clerics or Gift of Devotion characters worshiping (not attuned to) the following: Azuth, Deneir, Oghma, Mystra, and Savras. I have only included the most common "magic" or "knowledge" gods with existing roleplay in the Tower.