Curlin - as dominant at 4 as he was at 3?

Was Curlin a different horse this year compared to his 3 year old season, some people think that he wasn't the same horse especially after coming back from Dubai. This is a point that has to be taken into consideration because its common knowledge that most if not all horses after traveling 12,000 miles regress quite a bit after making the D.W.C. trip. If comparing Beyer numbers there is a great deal to be said about the fact that Steve Asmussen was able to keep Curlin in tip-top shape all year long. Here is a quote from an article by Handicapping Guru Gary West about his view of Curlin this year compared to last.
"From several sources, I’ve heard and read suggestions that Curlin lost the Classic because he isn’t quite the same horse he was last year, meaning not quite as good, and, further, that he’s not quite as good because he’s no longer on steroids. But I can’t find much to support the first part of that argument, which seems based largely on visual impressions.
I make my own speed figures and pace figures, but the Beyer numbers, since they’ve become common coin in handicapping, would probably serve better to make the point that Curlin was at least as good this year as last. I don’t mean to suggest that speed figures are definitive, but they do, I think, provide a useful measure of performance. And by that measure, in his graded stakes last year – and that’s tossing out only his maiden win – Curlin’s Beyer speed figures averaged 107.25.
In his graded stakes this year – and that’s tossing out only his first outing in Dubai – Curlin’s speed figures for the season averaged 110. (I’m giving him a 117 for the World Cup, which seems a solid, although conservative, number based on what we know about Well Armed and A.P. Arrow, who finished third and fourth in the race.) And in graded stakes on dirt – that’s tossing out the Man o’ War on turf and the Classic on Pro-ride – Curlin’s speed figures this year averaged 112.25. (Zenyatta, by the way, averaged 102.4 this year.) Curlin lost three races on dirt last year; none this year."