Let's use the ogre mage as an example. It was given a ridiculous ECL of 12 for god knows what reason. But the greater issue is that while it starts with a list of fairly potent abilities, they don't scale at all, so their usefulness decreases rapidly with level. How would you even start to assign a LA for this?
It gets flight at will, regen, sr and some SLAs, of which all but invis/darkness at-will are flat-out useless.
One solution I can think of is to give it a complete overhaul. Replace its SLAs with wiz9 spellcasting, increase racial HD to 8, and LA of +3. So you essentially have a caster with a LA+2 race, and enough hp so you don't croak the moment the kobold so much as breathes on you.
Yeah, I know the golden "Thou shall not give up caster lvs" rule, but being a flying, regenerating mage is novel enough that I am willing to suck up the penalty.
Now, what can we do about the astral deva? Cool abilities, but my experience with one tells me that while it is fairly hard to kill, its damage dealing capabilities is next to zero. So I am essentially deadweight in any party!