I think Hayden is a very good player. The fact that he got owned in the nineties when there were lots of great bowlers around works against him. Of course, you could argue he was a better player later on, which is a legitimate thing to say.
But then he did badly in really good swinging conditions against top quality bowling in Ashes 2005, averages 28 in New Zealand, averages 34 in South Africa, and averages 34 in England. So he is pegged as a flat track bully. That's a pretty harsh record to have for someone in an all time XI. Personally, thats just not good enough for me. I know you disagree and obviously that's fair enough - but unless he shows me something quite different, I wouldn't put him in the top five openers of all time. In fact, I'd put a couple of Aussie openers ahead of him.
I think since 2000, he has clearly been the best opener in Test cricket, but considering where and when he scores, it raises a lot of questions about him when comparing him to the all time greats.