The thing is with normal Top Gear, Clarkson is like the big head honcho out of all of them. He's definetely the biggest personality in the room and that's why he's the lead and he's the interviewer.
The American show lacks that completely. The three hosts just seem like your average annoying exactly the same dudes who are utterly generic in every way while UK's Top Gear has 3 very different people who have their own eccentricities that make them work together very well.
I've always hoped that US Top Gear could have had Jay Leno being the Clarkson of that show. Why couldn't Jay have just done that instead of all that late night crap?
May and Hammond are great but Clarkson is what makes the show and everyone knows it. Go watch a Jeremy Clarkson special (from the years that he left the original Top Gear (the one from 1967-1999 that was more documentary like) or one of his segments from the original Top Gear years (1989-1999) and it's instantly recognizable and "feels" just like modern Top Gear. There was no May or Hammond. It was actually Tiff Needle and it worked great as well. In the first series of modern Top Gear, May wasn't even on the show at all. It was Clarkson, Hammond, and a wierd guy telling you about car prices and deals in the UK.
Clarkson makes that show. All the other Top Gear's from Australia, Russia, etc. and now the US Top Gear are making the fatal mistake of not having a lead host in that manner but rather making it seem more like a show of 3 equals. You need the stubborn yet hilarious common-sense celebrity on there. You need a big American celebrity or comedian who enjoys cars.