This thread is interesting.
I personally made a mistake by thinking of the Octatrack as a replacement for my DAW.
Bear in mind with Mixing it's not... Because if you came from the DAW you probably looking for Mixing Tutorials or Books, and you put a finger in something which is normally not related to music arrangement. Back in the days and i think we can safely say that's is not the case today too. You don't necessarily have to send a finished projects EP (i mean mixed and mastered) to a label.
But if you intend to arrange a piece of music, actually every Pattern and Song mode on every machine is there for that purpose. Then comes automation and how they lived in time notion in your mind. If it's short and repetitive on OT with 4 bars and few tricks you should get it. If it's more evolving you should have to jam it... and record somewhere.
Every audio engineer i know or discussed prefer to mixing and mastering on a finished piece of music : i mean arranged and exported as separate tracks, or a bounce to -12 to -6dB without anything on the master. (no compression, no EQ no limiter, nothing.
So you can perfectly polish you tracks on a DAW at the end stage of the process.
OR, mixing it on an external mixer. For instance you can use the 4 Outs of the OT : as 4 mono outputs or, 2 mono outputs + 1 Stereo or, 2 stereo outputs (like 1 drum bus and 1 melody+fx+voice bus) and record with your preferred hardware multitrack.
The Octatrack is just like an instrument
Yes it's a dynamic performance sampler, i guess the name of the device is very clean and understandable at the end. To me it make sense.
Because well, the Octatrack doesn't exactly shine in surgically removing certain frequencies or subtly controlling dynamics with compression as far as I can tell.
Dont forget FILTER can be a very surgical EQ, and you also have Effects in this regard at your disposal.
If you used the Cue Outputs with your DAW and put a Spectrum on it, try the Filter and effects with Visual feedback and you will see there's a lot of perspective. I think it's really good way to re-LEARN how to re-APPROACH music with Ears only when you get far away from it because of the DAW (in some ways)...