Actually if you play a good solo bass line on the pedals, then most people take notice, as it gets away from the boring and monotony of Style play.
Another good way is to play a tune (That is normally played on the keyboard) on the pedalboard, such as flight of the bumble bee (For the more discerning customers) with the keyboards just used for the backing.
Playing 2 tunes simultaneously is also good, with the most popular being the Widor�s Toccata on the manuals while simultaneously playing star wars on the pedals.
Most of the rest of the things you mention can be done on most modern entertainment organs, without needing to use the pedals. (These can be used something else)
An arranger on its own is severely limited in what you can play manually without using boring backing styles, as you only have one keyboard, however add a set of bass pedals (And even a second keyboard) and you can go to a whole new level. (Convenience wise the arranger is great as it easy to carry and setup, but most players yearn for more)
Bill