Why Will Smith's Prince Ali failed...

There is a clip Will Smith's take on Prince Ali circling the internets... it stinks
So here's a quick explanation on the song of Prince Ali:
It's a big huge parade showcasing the awesomeness of Prince Ali thanks to the Genie's Magic. Since Jasmine is required to marry a prince Aladdin used his wish to become a prince. The parade is basically a big showing off Ali's status as a Prince as an attempt to impress the sultan and Jasmine.

Here's Will Smith's version

Feels a bit bland, lacking energy, and most importantly it doesn't show the subterfuge and Genie's cunning. Here will is literally spelling out all the coolness that is Prince Ali. Well technically speaking Robin Williams did the same thing, his Genie was more cunning and used deception to sell Ali's coolness.

Have a look at the Better version of Prince Ali.

Here we have a Genie that uses his magic to blend in with the crowds and sell Ali's awesomeness. He also uses Magic to allow Ali do feats of Superhuman strength, as well as subtly influencing the crowds... (i.e. Palace Guards)

The animated movie doesn't simply tell us that Ali is awesome. It SHOWS US hos awesomeness, not to mention that by blending with the crowds as different characters, the Genie is giving validity to his claims about Ali. In the liveaction version we only have Will Smith telling us that Ali is awesome and no one else does.

And this is the part where you go oh but Nefty we're talking about a life action movie not an animated movie and in animation you can do anything but live action has limitations.

To that I reply: computer-generated imagery and clever editing. Even in the live-action video we saw clever editing trick with when Genie comes out with "exotic type mammals" atop of a bunch of non mammals. We could have used some of that and have like a few extras with a Will Smith voice over their lines.

Maybe making Will Smith look like crap is Guy Ritchie's idea of Revenge after the horse that Will Smith was riding on an MTV award show stepped on Ritchie's foot...
In any case Will Smith's performance is lackluster and Guy Ritchie's direction is bad.  And all of this shows  a lack of understanding of what the original parade was truly trying to convey.