Pax said:
Because the full Ogre -- with better attributes and better natural armor -- has that very +2 level adjustment (and 4 giantish HD).
Then the question becomes, is the Ogre balanced at +2? I mean, we've pretty much accepted now that the Half-Ogre is too strong at +1, and compared to all the other races and classes in the books it's probably balanced at +2. If the only conflict then, ECL-wise, is with the Ogre then maybe they should be moved up, also.
If Ogre gives better bonuses than that, it should probably be a +3 then as a no-level race. Except that you're then being forced to take 4 monster HD, which should NOT count as ECL on a 1-for-1 basis due to their inherent suckage. Using Soldarin's system, each Giant HD counts as +0.5 ECL. That'd put the base Ogre at +5 ECL for a 4-HD race, which sounds about right.
That's why your +2HD fix works: 2 Giant HD adds 1 ECL, which means if it's now balanced as ECL +3 then without the HD it'd be +2...
In fact, let's run the entire Half-Ogre package through Soldarin's calculator:
http://soldarin.tripod.com/rpgpages/id5.html
Size (Large): +1.0
Speed (slower than normal for size): -0.2
AC (Natural +4): +0.8
Darkvision: 0.0
Treated as Giants: I'm going to call this one a Minor Power, since it mimics "immunity to a handful of spells". The ability to use giant-only items is more than counteracted by the ability to be a target of Bane weapons and racial abilities. +0.2
Ability Scores:
STR/DEX/CON: +6/-2/+2 = +0.6
INT/WIS/CHA: -2/0/-2 = -0.2
Total: +2.2. Yep, it's ECL +2 all right. And according to his tables, an Ogre (with 4 HD) is a +5 ECL, exactly like I said above.