As i said, West in last 10 years clearly showed what precedents mean absolutely nothing. Only politic and military power, only strong allies mean something - much as in later 19th century. In that perspective, China may actually recognize S. Ossetia to please Russia and gain russian support for various problems, including Tibet. US is right now hostily to China anyway.Except that it is so much more of an issue to China - situation not similar - they're not going to recognize independence.
They're looking to their own strategic interest (and perspective of legitimacy).
Tibet is VERY different from both S. Ossetia and Abkhazia as it is firmly controlled by Chinese power. If China somehow becomes so weak what it couldnt hold Tibet - no "precedents" will help it.
Look at Chechnya. Perfect example. Russia wasnt afraid to recognize S. Ossetia, although Chechnya have much more real chances to gain Independence than Tibet.
Actually, some goes with Taiwan. As long as China sufficiently strong - noone will recognize it. Once China becomes weak - noone will care about precedents.