Having been in a pretty busy touring band doing theatres (with our own PA) and Festivals of all sizes, AND being a sound op in a similar context, I have never been told by an engineer my bass is unacceptable, because I play quite a few, and pick them for the job in hand. In the tribute band I play a Fender American Jazz 5str, and it matches the music we do - but I absolutely hate the sound of the guitar. For every other music job I will play much nicer sounding basses - especially for the pop and jazz gigs. Also - if an engineer I did not know told me he didn't like the sound, he'd get a short response - probably two words. When I am doing sound, I often get sources that really don't sound very nice, in my opinion - but it's my job to do my best with whatever they give me. I did have a guy once criticise my playing because I tend to play most stuff up around frets 5-8ish, and use the bottom B a lot. This is tonally not as good as say the bottom F on the E string when I play it on the B, higher up - and one guy told me I should change. I smiled politely and said, thanks for the advice, but I'm happy thanks! As it happens, I'm totally happy with a straight DI going to the PA, My particular sound has no pedals or processing at all - maybe a bit of compression on the biggest rig - with 8 x10" speakers.
They get carried away a bit on Talkbass - clearly FOH engineers can demand what they like - but some seem to forget they are there to service the performers. Our job, doing sound, is to get the very best out of what we are presented with. It is not to request changes in what or how the performers do things?