As an avid player of 3E, I decided to stop by to look at its 3E conversion of birthright, something I haven't played in 3e yet. I had some thoughts after reading it, that I'd thought I'd share. I tried to be constructive in my approach. :)

- 7th ability score, like it, it fits superbly intot he mechanics of 3e
- Throrughness, Doom seems to cover all the bases
- Blood transfers, I really like Doom's take on that

- Multiclassing, we're supposed to collect regency from the class we're most like? 2e rules specifically state that multi/dual-class chars can collect regency as both classes, not one.
- New skills, all of these seem to be better suited to be a knowledge or profession skill. I certainly think having a Profession (Regent) is a possibility
- Domain Actions, I believe these should be tied to a skill (maybe even a different one depending on the action) and then applying modifiers to the way they process the action, for example, you send a letter or you lieutenant to do the dirty work. So the farther removed you are from the center of action, the less control you have, this should help balance with the fast acculmation of ranks
- the Blood ability score, I think using the bonus spell progression for an ability score would work very well here