Charles1dad,
My current tube pre is a well executed, pretty simple design and the best I have yet to hear. I share the same general assumptions as you, but I have not heard enough to say simple is best. I just don't know for sure. I would love to live with a well reviewed $70,000 pre for a month or so:-)
Over the years I have assembled many good sounding systems. One that was particularly pleasing included 3.5 watt set amps, zero oversampling battery powered dac, belt drive transport, single driver horn speakers and both a passive and simple active preamp. Great sounding system that however did not match the realism of my current system. My current system is more complex if you will. Soundlab M1 speakers with an active crossover which is much more complex then my past horn speaker.
My current 600 watt/channel amp is more complex then my 3.5 watt SET amps to be sure and so on..However the end result of this system is more like the real thing.
I bet I could assemble another simple system as good as what I now think is my reference, but just have not gone in that direction as I am most content.
In the end, I am not sure one way is better then the other. I just don't know.