Re: Hit Points
Dread Necro d6 HP, averages 3.5 per level.
Undead d12 HP, averages 6.5 per level.
Plus, add in some modifiers depending on who creates you... and if desecrate is in effect...
Forgive me if the formatting doesn't carry over, but I'm going to cut/paste something from a Word file:
Only Libris Mortis - Corpsecrafter calls out undead created with spells and not rituals (like necropolitans)... even then, you could argue that the "Raise" part is seperate.
Instead of reading the "or" as: Raise with any necromancy spell, or create with any necromancy spell.
Interperate it as: Raise (period), or create with any necromancy spell.
With it, that's another +8 HP/HD if you can get the right people to cooperate in creating you as undead. Without it, you could get up to +6 HP/HD. But still, that's up to your DM. I don't think it hurts to ask.
Combine that with the extra 3 HP/HD undead get over live dread necromancers, and that's plenty of HP IMHO.
Re: destructive retribution, Like corpsecrafter above, it depends upon how your DM reads it. Since Spell-Like abilites are not spells, the feat may not apply. For my games, I house rule that the caster can pick and choose when to use it (like metamagic feats). IMHO, Feats are meant to be an advantage, not a dissadvantage.
Re: how to spellstich, I treat it like magic item creation (since it requires Craft Wondrous Item). In my games, all the requirements for item creation apply.
As I am reading the replies, I am formulating a reply in my head... It wasn't until I got to the bottom that I saw your comment about using more Spectral Hand. I was going to say "More Spectral Hand" along with "More Cowbell".