Heh. Hardhead apparently isn't interested in a debate based on 3e metaphysics; he wants 2e.
Fair enough...
Well, then - here goes:
Hardhead said:
A vrock is a freakin' greater tanar'ri
Methinks that you're rattling your bone-box a bit too quickly there, friend.
Because actually, back in 2e, a vrock used to be a
true tanar'ri - i.e., the "rank" just above greater tanar'ri.
... one that has proved itself in battle time and time again in battles against the baatezu and the celestials. You don't get to be a vrock, unless you've got lots of experience, and are a powerful creature.
The way you're putting it, this sounds awfully like Diablo-style "killing stuff and levelling." (Disclaimer: The practice of which I'm not dissin' here; I loved me some Diablo "back in the day" when it was released. Mmm - good memories...

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And while such behavior could certainly be helpful on a tanar'ri's quest for more power, it wasn't the way to higher tanar'ri forms itself, but instead merely a
tool.
In fact, the tanar'ri "have no set procedures for ascending from one rank to another. Instead, their promotions hinge on belief - from candidate and judges alike. If a tanar'ri convinces its brethren that it's stronger, more cunning, and more powerful than they are, that perception eventually becomes a reality, and the fiend transforms. It's a strange mix of self-worth and posturing."
So, metaphysically, you can have whatever you want - including Tanar'ri who have managed to will themselves into Vrocks but don't (yet) have the necessary amount of willpower and prestige - or experience with Vrockdom- to have access to all their potential powers.
(BTW, that any kind of "standard procedure" among creatures of primal chaos like Tanar'ri is inappropriate anyway, IMO.)
(Tangent: Come to think of it, I
also can quite easily see newly-Vrocked Tanar'ri who just aren't yet accustomed so well to their new form that they can utilize all of its powers.)
And if you really
just don't want to use the Savage Species system for Tanar'ri (and/or possibly other creatures) but instead some 2e rationale or whatever floats your boat, there's no problem, really; just ditch the few fully-listed class advancements for Tanar'ri (et al) and insist that the entire ECL cost (which is also given in Savage Species) must be paid at once (also, see below for an idea on how to do that after character creation).
In fact, he could have made a much cooler class that started out as a Dretch and changed forms as they leveled and advanced through the tanar'ri ranks. That'd have been really nifty.
With Savage Species, that's not very hard to do on your own, IMO.
Just take a few pointers from the Blackguard and let them trade in their Manes ECL cost, plus a sufficient number of PC/Pr class levels, for the Vrock ECL cost as soon as they achieve the necessary in-character requirements.
In closing, a few tangential questions on which I'd like to hear your opinion on, Hardhead:
Does your EN World nick name have to do with the Harmonium?
Further, you seem opposed to broad changes for their own sake. So tell me - what do you think about the adventure modules "Faction War" and "Die, Vecna, Die?"
(Personally, I don't own FW but I'm not a big fan of what I heard about it. I'd like to run DVD one day, though, but only with a few... changes... of my own which make more sense to me.

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