Racial HD counting towards ECL. What?!

[Kylarra]

Yes, but I'm not talking about Rakshasa's. What if an ogre wanted to be a druid, or something? Level 7 druids vs. level 1 druid? Yeah...

So you want to take something with decent physical stats, and trying to make them analogous to full casters... why again?

If you're making this decision as a PC you're deliberately choosing suboptimal choices and even then you can go ahead and buy off your LA eventually (under most circumstances), rendering you effectively some sort of fighter/caster multiclass, which should obviously leave you weaker [in terms of spellcasting] than a full caster.

If we're talking about NPCs then read the rules for non-associated class levels.