Personally I think a project per song is excessive to say the least.
It all depends on how you envision song construction. Some people want to nail every note/beat & have it written in stone. Others leave lots of room for extensive improvisation.
I come from a song writing/DAW/Tracker background so I started off trying to cram every little nuance in there but ultimately it left me nowhere to go.
I think this approach is fine if your goal is record it & that’s the end product. In this scenario I’d use the arranger too as it allows a lot more flexibility.
For me I found having the bare bones preprogrammed then just going for it really helped my improvisation, technique & knowledge of the machine(s).
If this improvisational approach appeals then less is definitely more!
On a similar note, I went to see Lucy, the Luc Besson movie, the other night & there’s a comment in there about ‘being v having’. A reference to German psychologist Erich Fromm no doubt.
Point is this, (& no I’m not smoking crack), once you’ve established a complex pattern, then a few more, then several songs worth, revisiting them is a bloody nightmare!
Trying to remember where everything is & how it’s supposed to unravel is next to impossible. Now try that when you’ve got all 5 Elektron boxes synced up, arghh…what was supposed to be fun is now doing my head in!
Bottom line is that you now ‘Have’ a load of patterns that own you if you want to perform.
If however you just hint at direction, suggest a riff/chord/beat/sample/swing factor/tempo etc you can live in the moment , ‘Being’ creative & developing the theme.
To begin with I’d try working with a bank per song. 16 patterns should be enough, especially on the AR where you can use ReTrig for fills, employ mute masks/scenes/perf & save the pattern to the buffer to return to later. I’m currently using no more than 4 patterns & a lot of the time I’m only using 1.
Hope some of that helps, right where’s my pipe 
