I wanted to suggest adding a skeleton lord to the animate dead summon tree, as the new capstone summon starting at level 15. It would be a mild improvement over the skeletal chieftain, (but more on that at the end). Animate dead would have the following progression:
Vanilla:caster level summon1 to 5 Tyrantfog Zombie
6 to 9 Skeletal Warrior
10+ Skeletal Chieftain
POTM:
caster level summon1 to 5 Tyrantfog Zombie
6 to 9 Skeletal Warrior
10 to 14 Skeletal Chieftain
15+ Skeleton Lord
Why?:I play a dedicated necromancer, and it is great fun. The bread and butter of the necromancer from levels 3-13 is the spell animate dead. Animate dead starts to lose some steam around level 10, (and for arcane casters perhaps never gains steam). For this reason, I suggest adding one additional summon to the list that is incrementally stronger than the previous one.
The skeletal lord! My thought is actually to take the skeletal chieftain, and just add +2 fighter levels, and +2 ac to it. This follows the progression of the rest of the summons:
Skeletal Warrior: 13 AC, lvl 4 fighter, lvl 1 undead.
Skeletal Cheiftain: 15 AC, lvl 6 fighter, lvl 1 undead.
Skeletal Lord: 17 AC, lvl 8 fighter, lvl 1 undead.
I'm not sure how this will be received, but speaking from my own experience this change would appreciably improve necromancy as a dedicated character path. Furthermore it would help both the arcane and divine casters that want to pursue necromancy, which I know has been a topic of complaint in the past. It's also conservative and should fit right in.