Actually, Baxter is probably fourth on that list in terms of TH props, it's just he came between them. Noriega, Darwin and now Alexander (as he can keep his bind up) are all probably ahead of him technically. All three were probably better around the field too. I see no reason to give it to Baxter than caps, which he got as we had nothing.
What I like about Baxter is that he improved. He was perhaps the worst TH prop in 2003 of all the top 10 rugby nations, but improved such that, by 2008, he could hold his own. He still had problems with collapsing on the hit too often, which is one reason, I think, that he got targetted and penalised.
Anyway, nothing against him as he's a great guy off the field, but Baxter being TH prop of the decade would probably be a farce in my opinion.