No witty remark is going to beat the beauty that's three posts above this. Go enjoy it if you haven't seen it before yet.
By the way, has anyone noticed slaad are 'usually' chaotic neutral, rather than 'always'? Then again, I guess that if they were inherently bound to one alignment, they'd hardly be creatures of pure chaos.
Also, the slaad brooder prestige class will be largely ignored for being just not that interesting.
7 outsider RHD, large size, good physical but bad mental stats, and the random immunities and resistances every outsider seems to get. Sonic immunity is actually kinda neat if only for being so rare, and fast healing is welcome on every character.
Pounce for free is very neat, especially with such a strong bite attack. The claws are less impressive, unless you're the kind of person who likes the idea of creating giant armies of self-propagating spawn (and in that case: be a shadow).
Red slaadi can once per day perform a Stunning Croak, which is a short-lasting unfriendly Save or Suck in a small area that eats up your action that turn. I fail to be impressed. They can also attempt to Summon another red slaad each day, though it's not going to appear most of the time.
All things considered, +2 LA should be fine.
One more HD than reds, and small bonuses to strength, constitution and charisma compared to them as well. Blues, however, get four rather than two claw attacks, which also have dramatically increased in power. Their bite attack now spreads a disease, of all things, which turns its victims into red slaadi. Ah yes, I suppose I shall bite this guy then wait around for a few weeks until he finally turns into an entropic megafrog that's still hostile to me.
Rather than Pounce and Stunning Croak, blues get at-will Hold Person, Passwall and Telekinesis, and 1/day Chaos Hammer, all at CL 8. Those are some quite powerful spells, and combined with the sheer melee might and great HD, this seems like another +2 to me.
9 HD this time. Better mental stats and slightly worse physical ones than the two previous slaadi, okay natural attacks, and more of the same random resistances and immunities. Also opposable thumbs, which reds and blues very possibly don't have.
Change Shape into large or medium humanoids is useful, but only for disguise.
Finally, more SLAs than you can shake a stick at (unless the stick is a Wand of Dispel Magic, of course), starting with at-will Chaos Hammer, Detect Magic, Detect Thoughts, Fear, Protection From Law, See Invisibility, and Shatter. It's not bad per se, but the fact that clerics got the highest-level thing a few levels ago is somewhat sad. 3/day Dispel Law, Deeper Darkness and Fireball are little better.
In the end, I think this critter too deserves +1 LA.