Atmas do you design to what you think sounds great, or is it a case of trying to please some of the people, most of the time ?? I expect in this industry(at this end of the industry) that its driven by passionate artisans who are designing towards their ultimate personal taste.
I'm looking to improve the performance of the circuit all the time. Until you asked this question, it never occurred to me to try to go for a sound that someone else likes. First off I don't have any idea how I would get into their head to really know what that was :)
So I just try to get as much performance as I can, doing it according to the design principles that have guided me now for several decades. To that end: eliminate sources of distortion (some examples of distortion sources are transistors, pentodes and transformers), particularly the kinds of distortion that the human ear finds objectionable. I don't care so much about what distortion if the ear does *not* care, so I do place a value on listening!
I go for simple circuits; a lot of people are surprised to learn that our OTLs have a simpler signal path than even SETs have (only one stage of gain).
I agree to a certain degree with Charles1dad in that what works for you is fine- that is what works for you. But to that I add that that is in your experience, and what I have found is that no-one has experienced everything. There is always room for improvement. So really its more a matter of if its 'good enough'.
One thing that I find interesting is that we audiophiles use much the same language to describe sound ('soundstage', 'relaxed', 'dynamics', etc.) but this language fails to convey the intensity of the experience. So as a result on the Internet two audiophiles can use the exact same expression although one is describing a $600 transistor amp and the other a $50,000 tube amp. Their experience is worlds apart but the language makes it sound like its exactly the same.
So we still have to audition stuff- no way around it.
Have a good holiday!