I think a lot of the more forward looking arranger players here have lamented the lack of arpeggiator features on arrangers (the two are quite different). Until someone finally melds the two together, neither does the job of BOTH.

The thing about arps on a WS that differs the most from an arranger is that EVERYTHING must be cued a bar in advance. We all have got very used to the system that, when we ask for a fill, we get it IMMEDIATELY, in time with the music. Ask for it on beat 2 or 3, you get it to drop in on beats 2 or 3.

But workstation arp players, AFAIK, even if you have an arp fill (not a whole lot of fills in most of the factory content!), if you ask for it on beat 2 or 3, you either get nothing until beat one of the NEXT bar, or you get the arp playing the second you ask for it, but it starts on the one of the fill, whether the arp player plays it on the one or not...

In a way, it's like Intro and Ending divisions, or calling Variations without a fill... fine if you call them up in advance. Not so fine if you want them in the middle of a bar!

Adding this one simple element (starting an arp on the beat that it is asked for, in the middle, that is) to WS arp players would allow us to use them as arrangers fairly easily, especially if these one-shot arps (that's what a fill is) are allowed to have a destination arp so that a particular fill/arp goes to another arp which is the next Variation in arranger-speak.

Until they do, though, you have to change HOW you play quite considerably.