I personally (of course, just my opinion) would just mix it how i think it sounds best, the customer has the last word anyway. But of course, if the customer always says "It has too much bass" than maybe there is something one need to adjust, that is true.
Yes, the client of course has the last word but I generally wouldn’t base my working practice on clients’ preferences because they can be a bit whacky and they usually have a limited understanding. Typically they’ll feel something isn’t quite how they want it but the suggestion they’ll give you to put it right is incorrect, so they might say something like “I need a bit more bass” but when you add more bass they realise it’s even worse and what they actually wanted was more punch in a bass instrument and the solution was actually completely different, a bit more mid for example (or something else). You eventually learn to “read between the lines” of what clients request. However, it does depend on the client, if Dave Gilmour says his guitar has a bit too much bass or Placido Domingo says the same about his voice, then their long and illustrious experience of their own sound production warrants a bit more influence.
Hmmm if you give the Album to 5 Studios, you get 5 results with 5 different amounts of bass.
True but how much influence that has depends on the producer and also the studio. If for example one of those studios is Abbey Road and the others are talented self taught guys with great setups in their basement, which would influence you more? I was very lucky that I worked a fair amount at some world class studios, Abbey Road, Air, CTS, The Hit Factory, etc., with some of the world’s best engineers and if they told you something, then you listened. Likewise, when I went to test a score mix at a top dubbing theatre with an Oscar winning re-recording engineer and when I arrived I had to sit and be quiet for 10 minutes because he hadn’t finished recording ADR with Al Pacino, or you do the same with a double Oscar winning re-recording engineer who mixed some of the most iconic films in history and while you’re having coffee with him Tim Burton phones him for some advice, again, you listen carefully to their observations and advice, especially if you’ve only been in the business for a few years.
I don’t mean to “name drop” with all the above, just to explain that it very much depends on what you’re being told, where and by whom. Of course these days you can also verify what you’re being told with all the spectral and other analysis tools at our disposal.
But unrelated to that, if you have an reference how an Cymbal sounds in real life, your job as Mixing/Mastering Engineer is, of course, to make it sound as close to the real thing as possible, without any added "Taste", as long as the customer wants that.
And to my experience, it is not that common that the customer wants true to live. Especially Metal Bands often want their Drum kit to sound nothing like it sounded in real life

but that is a whole different story.
Drum kits in metal bands are quite an extreme example but that’s true to a greater or lesser extent across pretty much every genre. Clients are more interested in “good” than “accurate” (true to life), although to be “good” will usually also require some amount of accuracy to RL. Experienced professional musicians will know that what they hear when performing their instrument will be significantly different to what the audience hear many meters away, so they will usually not want exactly “as it sounds in real life”, they want it to sound as good as possible to a hypothetical audience and this is true across all genres, even classical.
I therefore don’t agree that it’s the engineers’ job “
to make it sound as close to the real thing as possible”! Certainly you need to know what it sounds like in real life but that is never the determining factor, just a greater or lesser influence. The job of an engineer is as much artistic as technical, it’s to make it sound “good”, not as close to the real thing as possible!
In this particular case though, little of the above applies. I’m not sure how far past the OP you read, but the issue was not frustration with the sound of cymbals, it was that the OP didn’t know what a closed hi-hat is, and expected it to sound like and have the decay of a splash cymbal.
G