I think you are confusing the base humanoid with the base creature. They are the two halves to the tauric creature. The text states that the level adjustment of the template is the base humanoid's +3, therefore if you were to add level adjustment to the creature half, you wouldn't have to pay for it with this template.
I was getting the terms confused and my last post was to clarify we both understand how the level adjustment from templates works. We do. That's good.
You were saying that you can add other templates to the base creature (the animal, beast, vermin) and you wouldn't have to pay. Technically this is right. Any DM I know would smack you hard if you found a combo that worked but RAW you are completely accurate.
To a point, as soon as those templates change the base creature away from animal, vermin or beast they would no longer qualify for the Tauric template. Half-celestial changes the base creature to Outsider (as I already said) and therefore would negate their ability to be used in tauric template.
You could add it to the tauric creature (the finished product) after the fact as I said in my previous post.
Except that when player B tries to make a tauric fighter he chooses for the humanoid part an elf (lvl adjustment 0) and for the animal part a half-masomething overtemplated legendary beast of monstrosity (lvl adjustment 45 because of all the templates). Then he looks at the rules for tauric and just has to be lvl addjustment 3 (humanoid+3). So he can still be a lvl 13 fighter and be ECl 16.
Well as I just pointed out, yes he could pick elf (I picked human as an obvious 0 LA creature but any humanoid would have worked) but trying to find that one massively overtemplated legendary beast wouldn't have worked. There are a lot of powerful beasts which would work, granted, but templates almost always change the type to no longer work with the Tauric template.
A sneaky alternative is to find the most powerful four legged creatures out there. Yes, this is an option. Or to find a template that changes any creature to a vermin with four legs of medium or large size only. Yes that would work too.
the 'base' creature referred to is NOT, as you seem to assume, the templateless humanoid you started from, but the creature the template is added to.
If you add the tauric template to a half-celestial bear, you add both the LA of the half-celestial template and the LA for the tauric template to the bear.
The revision done by WotC explicitly says the LA applies to the humanoid (the one that advances) and not the base creature. I only went with a limited understanding of not reading the actual books and merely going on the revised pdf of which I was linked.
Either way I needed to know that afluty and I understood how templates are (usually) acquired and applied to a character.
Also, you should read the Tauric template, as clearly changing the type from animal to outsider will no longer allow them to become tauric.
I think the confusion here stems from the idea that, somehow, the base creature's level adjustment starts at 0.
It starts at whatever the base creature's level adjustment is.
The base creature's level adjustment according to tauric really doesn't matter.
In summary, yes what allowing a player access to any creature which falls into the criteria listed and getting the powers listed in the description is a little silly for +3 LA. That being said, as far as I find that's exactly what it costs. A more rational idea
[see below in black] would have been something like what WotC did in the 3.5 MM1 for Natural (and artificial) Lycanthropes. They didn't but it would be a natural alternative.
Oh, and I made my previous two posts without use of the MM2 or MM1. Any confusions I had or I caused were unintentional but even after grabbing the books and physically looking through, I was still confused by afluty's question.
Oh for those who don't have any idea what that looks like..
Level adjustment for a lycanthrope has two versions depending on if natural or afflicted. Natural have control and afflicted don't.
"Same as base creature +2 (afflicted) or +3 (natural). In addition, a lycanthrope's character level is increased by the number of racial hit dice the base animal has."
A note like the above changing racial hit dice for level adjustment and hit dice would have solved this entire thread.