Its obvious that most Mac fans don't like the new Leopard UI, therefore, is it possible that Apple may do a whole new UI change before the October release?

I just don't think that Apple is going to release Leopard with the current UI, they know it sucks, so it would be a smart choice to change it.

One can only hope, but since the "incredible" transparent menubar and 3D dock were such highlights of the the last WWDC its probably doubtful.

I'm sure they will tweak it but it would be nice if it was a user option.
I would have been happy with the other changes that brought functionality, (spaces, stacks, coverflow in finder, quick look, etc).

Although they are trying to make the current window more focused with these changes, (dock, shadows, menubar), we know not everyone perceives things the same thing and forcing changes like that to everyone is IMHO a mistake. (Assuming it doesn't change.)

That's an opinion. And obviously not one Apple shares. I highly doubt they will change it, not after it was pretty much the focus of the keynote!

I don't think it's that bad, I was hoping for a unified, metal-free, pinstripe-free interface. I can live without the reflective dock floor and transparent menu bar, but they're not a big issue for me. The menu bar can be easily changed anyway.

I think Leopard looks fine, I don't know what the big fuss is about.

I really just hope they stick with the Aqua scrollbars and don't try use iTunes 7 style grey bars...

The UI does grow on you after a while...and, all of the regular apps for editing the UI should be updated to run with Leopard at some point. (quicksilver, etc)