After reading all of this debate let me say something:

when it comes to playing arranger keyboards, how well you perform is how tactfully you use sounds. you may want to sound just like the real song or add some extra taste and color.
IMO the player who thinks and sets up his instrument before playing, will perform better. So fast operating functions may not make huge differences. I remember a wedding where the player(who thought he is a pro!) was asked to play a song which certainly he had no pre-sets for it. with his big korg although he used some of those fast functions, he performed very very ordinary and in my opinion somehow nonsense.
my brother that is just a listener told me that you play this song far too better and more exciting(I am a hobbyist player).

this is where fast swithing or grooving functions are not that much helpful.

all I want to say is: if you already set up your instrument for a song, there will be nothing you can do with g-70 that you cant do with tyros although ways are different.