I notice that it seems like Mask has been taking some efforts to add some balance, and it seems to be working.
A couple other suggestions, due to recent threads:
Attacks of Opportunity. Normally, in SRD, if you cast a spell while in melee range with another, you provoke attacks of opportunity. This can be avoided by casting defensively (which requires a concentration check, but hey, so does getting hit).
I don't think this would be overly untoward, especially if all casters (including bards) were given a 'defensivecasting' combat mode, in which they lose the ability to perform melee attacks, but do not provoke attacks of opportunity. Perhaps, if they have the expertise feat, this defensivecasting mode could also grant an AC bonus as it would in regular defensive mode. (Defensive mode normally applies a penalty to attack, but, obviously, that wouldn't be needed in this case, as you're not attacking)