Please, for over 10 years Haiku has looked the same 
if you don’t want to actually tinker with the UI, at least refresh the live installer. My suggestion is to load it to the desktop and run the installer from the icon. And the ‘Tips of the day’ window with a light tutorial on how to use the Haiku system (animation).
In what way would you like the UI to change?
You can do that already. Just select “Try Haiku” in the first installer menu. This get’s you straight to the desktop, and you can then start the installer from deskbar. Not really sure what the advantage of this approach is, but you can do it.
There’s a link to our very detailed user guide on the desktop of a freshly installed system. No animations though 
This is a corrupt my idea, my post