Oh please there's a whole segment of Star Trek fandom decrying the 'fanwank' of ST: D (IE OMG! They're doing stuff related to 'Spock' and 'Sarek'...it's so 'small universe', and any other TOS references they make.)
And if they weren't doing any references, these same people would cry: "See, 50 years of Star Trek and they use NONE of it in ST: D..."
It's not a 'strawman excuse' when for an entire fan segment, any call back or use of previously existing characters is considered 'fanwank' or 'unoriginal'.
Again damned if they do, damned if they don't.
Here is the thing though: You're over-generalizing, where in reality it depends on the
context of each case
:
To give a non-controversial Star Wars example:
Say you make a new series set in the timeframe between the original and the prequel-trilogy (aka between Episode III and Episode IV). There are certain things
expected to appear, and other where it's clearly fanwank.
For example: In this time period, it should absolutely be expected that "The Empire" is a large political player, when it shows up they're
often using Star Destroyers and TIE fighters, and that Stormtroopers appear on many different planets.
These elements SHOULD appear, because they are a large factor in the worldbuilding of said time period. But if, say, a young Boba Fett, a young Han Solo, an early Death Star and Obi Wan all appear one after another seemingly at random -
that's fanwank. Because
these elements are supposed to be
super rare in this time period.
See? It's pretty easy.
A positive example for DISCO is the appereance of Andorians and Tellarites: They are big players in the Federation, especially at this time, so it's great to see them! Also the appereance of Sarek alone is not the issue - he's a famous ambassador, it makes sense for him to be involved in the big political situation of the time.
It's just
the other times where DISCO fails that test when it's called out: Burnham being Spocks long lost sibling, also independantly stumbling upon the Mirror Universe, Harry Mudd etc. - each of these should be a singular, unique, rare event. Having them
all together stretches disbelief.