First, ZO is fantastic and has helped my skiing enormously, I cannot imagine going back. I also tend to follow the 'shut up and ski' philosophy but I am a geek as well and enjoy thinking about some of this.
The voodoo parameters @Than_Bogan speaks of are a result of all the complaining about the original ZO versions. They represent what we cannot quantify about how to couple the 'feel' of the pull to a consistent speed.
If I recall correctly, the original (perhaps just he prototype versions) of ZO had no parameters at all, just set a speed and go. As an engineer this was beautiful, and just what some of you are saying you would like. Of course, everyone hated it, so much so that the ABC was introduced, then ABC/123, now ABC/123+/-.
To eliminate ABC/123+/-, or generally simplify the software, would require a way to predict how the pull would 'feel' for every individual, in advance without an input to the software.
ZO has to do this on some level for the engine (the software has to predict what an engine will do when it gives it a signal to go faster), I presume they use an empirical study to characterize an engine or series of engines and have hard programmed that information into the software. So how do you do that for each individual skier with respect to feel?
I don't know, but it is interesting to think about. Personally, I think asking the user for a preference is a fine compromise. However, I may be biased as I don't think ZO is an issue anyway.