Point taken.
My concern is that the blood mage is in a truenamer-like position in which operating at his full potential becomes more difficult as he advances in level, rather than less. A quick review, assuming a character who starts with 18 Con and 18 Cha, then scales to 26 Con and 26 Cha by level 18
{table=head]Level|Avg hp|Hp to cast all spells|% of total
1st|8|4|50%
6th|49|32|65%
10th|89|89|100%
14th|151|175|116%
18th|171|276|161%[/table]
For this analysis I'm leaving out the SLAs that grant temp hp and the option to burn hp and/or Con when casting spells, but I think this demonstrates my concern. Also, you can see that at higher levels, a blood mage would need a wand factory to support him if he tried to use the wand of CLW trick to support his casting.
I would propose that "must harm self to use class features" is a significant and overarching drawback, especially when the bulk of your spell list is intended to be cast while other people are trying to kill you.
This is reasonable. You might also consider an ability like the warlock's fiendish resilience, or an ability that grants fast healing but disables spellcasting while in use (thus, it's for out of combat healing only).
My suggested text would simply be "The blood mage may not benefit from any effect that would add additional spells to his class spell list or list of blood mage spells known."
Concerns would be (using "free" to describe an XP or GP cost paid with hp in an out-of-combat setting where the damage can be healed with no risk):
- Ultimate Magus to acquire free permanency in conjunction with access to the wizard spells compatible with permanency.
- Arcane Disciple to acquire free miracle.
- Arcane Disciple to acquire the Healing domain.
- Mother Cyst to acquire necrotic tumor (which provides dominated minions for use with blood pact) and necrotic empowerment (which provides 100 temp hp per casting).
- Sand Shaper to acquire free awaken sand (for unlimited minions).
- Rainbow Servant to acquire free raise dead/resurrection/restoration/greater restoration/mass restoration/stalwart pact/renewal pact/death pact.
Basically, bloodletting makes this a Tier 2 class, able to break the game in a variety of ways, depending on build. However, with a hard restriction on expanding the list, you could close that can of worms and restore this to the Tier 3 role you were envisioning.