My astral and nature picks were motivated less by blesses than by the desire to have access to Dispel, Wish, Gift of Reason, Faerie Queen, Gift of Health, Ring of Sorcery/Wizardry forging (which I find very useful in jump-starting any number of booster paths), and yes, Tartarians. All late-game stuff, with my scales and battlemages intended to carry me through the mid-game. I might have settled for N3 instead of N4 except for the fact that, yes, regen is a nice bonus on sepulchrals and mages, but N4 also means that I can forge a thistle mace to forge a treelord staff to summon Tarrasques if I want to.
Access to Dispel has become more important to me since LA Ermor dropped Burden of Time on me in one game and it became clear that none of the AIs had any interest in dispelling it. It wasn't crippling given that I had skull mentors, but it just wasn't any fun and I wanted it to go away. LA Agartha has a tiny bit of astral on mages but I'm more comfortable with S5 or S6. (On a master lich Mind Duel vulnerability doesn't matter.)
I'll reiterate that I'm no kind of pro, especially at LA Agartha, but so far this is working for me. I'm leading in income and second in provinces and research and steadily consuming MA Ulm and a neglected corner of indies. I have more money than I know what to do with so I'm just building temples and forts; this is far superior to my previous strategy (D9E9S4N4 master lich, Dom 4, Order-3 Misfortune-3 Death-3 Cold-3 I think on the theory that gems matter more than cash in the late game) which almost got me dominion killed and had me constantly strapped for cash. Not a really huge change in the way I spent pretender points, but now it's not a temptation to buy blindfighters. Cave Knights and crossbowmen are my friends, and Cave Drakes are upkeep-free.
Doesn't hurt that I've gotten lucky in my site-searching, either. +18 death gems per turn, summer of year 3.
-Max
P.S. I haven't used any thugs or I'd speak up; I think I mentioned that I did try a Tomb Oracle with the marble breastplate thing + Charcoal Shield + Fire Brand + Soul Vortex towards the end of one game that I was losing, but it wasn't enough to turn the game around. It's hard to go wrong with Wraith Lords, though, even if it's hard to forge Winged Boots for them.