It's not so much the number of channels specifically but rather the data density at a given moment. For example,say, 4 channels of note ons / offs equals 100% X. Add another channel and you have 120% X. BUT, get crazy on some of those with lots of pitchbend and/or other continuous controllers and suddenly it's 400% X. (Yeah, I know this is a lousy example but it's late).
I used an SE30 for quite a while to record and compile sequenced songs and the biggest problem I had was, what else?- the screen.
You can quickly get to where you're zooming in and out and in and out…playin' all night and the music's all ri…… sorry. Plus, anytime you're looking at multiple tracks, it's a lot easier to see what's going on when each one's a different color. So…
I would recommend using one of the larger computers just for the comfort factor.