There was lots of discussion about this on the FR forums of the WotC boards. Unfortunately, they delete messages older than 30 days in all forums (except archives, of course

), so I can't give a link. Because I had the response of an official on that matter.
Basically, the reason they shaft some races is that they want to "not incite players to play monsters", which is logically equivalent to "incite players not to play monsters". They seems to consider a DM is too weak-willed to say he don't want a bulette barbarian in his group, so they give ECL +24 to the bulette, so no one will want to play one and the problem is solved. That's a bit caricatural, but that's it.
Now, some monsters are allowed (drows), but those who don't have an inherent coolness factor ("look, I'm a drizzt-look-alike") are heavily penalized.
The Hobgoblin is (now) ECL +1, by the way. Compare with the "x person"-spells-immune, energy resistant, free-spell-per-day-casting, planetouched, and tell me if that's worth as much as +4 to Move Silently.
Ain't it crap ? ECL are to be determined by the DM on a case-by-case basis, IMHO. And even if I know ECL and CR does not measure the same thing, I think that when the ECL is 4 or 5 times bigger than the CR, one of the two is wrong. Seriously. If a 2HD ogre really worth an ECL +7 ? Compare a 8th-level human fighter and a 1st-level ogre fighter. Then 8th-level human rogue and 1st-level human rogue. Then same wthing with cleric and wizard, and if you're not bored, try paladin, bard, ranger, druid, sorcerer, barbarian and monk also. If in one case the ogre with 1 level is overwhelmingly better than the human with 8, the ECL is justified.
But I'm afraid it is not.