What you see as a benefit I see as unnecessary biased opinion. I also see these designations being used to push certain personally favored characteristics as a form of stolen authority. "Well clearly pop3/xyz/whatever shrimp used the term '002', so clearly this means that this carrier will have [fill in the blank]". There is also absolutely nothing constraining you from expounding on what you think CV-18 will look like, while "002" means you are claiming without evidence that CV-18 will be an entirely different class from CV-16/17. Also, note that "002" doesn't actually capture ANY characteristic apart from it being a different class from 001/A. Does "002" mean nuclear? Does it mean CATOBAR? Does it mean 80,000+ tons? That you feel these designations capture information in addition to class distinctions simply means that you have inserted your own biases into these designations,.
I'm not sure which individuals you've seen using designations like 001A or 002 to describe characteristics as a form of "stolen authority" -- some people have used hypothetical designations like 001B or 002A or 003, but in most cases I believe they were spoken in full knowledge that those designations have yet to be used by credible individuals in any meaningful capacity.
But the characteristics for 001A and 002 at this stage have mostly been consistent by people who have used them, and if they are used in a way which broaches the characteristics circulated by the rumours then more often than not that is pointed out to the individual in question, no harm done.
Like it or not, rumours are central to PLA watching, and they help to limit our area of uncertainty as to what a certain product or system could look like or is meant to be, to provide a consensus until new information comes to light. Obviously the interpretation of those rumours will be up to one's own biases, but then again any indicators or evidence can always be modified based on one's own biases.
That's why we have discussions to debate what various rumours can mean, and to use those discussions to reach a likely consensus, while fully understanding that new information or rumours could turn previous consensuses up on its head.
But that depends on everyone agreeing on some fundamentals first, like the role of rumours and big shrimps in PLA watching. I suppose you could call this a bias that differentiates the various sides if you really want to.
And FYI, at this point the current consensus based on existing rumours is that 002 will be a conventionally powered CATOBAR carrier whose full displacement has been described to be between below 80k tons and slightly above 80k tons.The exact type of conventional propulsion, the number of catapults, etc, are unknown or at least lacking in solid support.
That is information gleaned over years of occasional posts by various big shrimps. I'm not sure how long you've been PLA watching but I think if you go onto most PLA related forums and ask what 002 will look like, most of the people who have been part of the community for longer periods would likely give a description very similar to what I provided.
Now, I can understand your skepticism towards rumours and even see interpretations of rumours as biases, but that's just how the game is played. Back when J-20 was still J-XX in the mid to late 2000s a consensus had already been reached on what the aircraft would likely look like. In the early 2010s, a consensus had already been reached about what kind of carrier the Navy would want after ex-Varyag (then unnamed) was commissioned, years before 001A began construction.
The record is not time-perfect on every single instance, and everyone knows that new rumours can change the equation. But to reject all that, and reduce the discussion to only the simplest and most basic of aspects, and then to call people's differing interpretations of rumours and discussion as fanboyism is frankly a little bit offensive to the methodology and the very respectable history of predictions that have been made through the interpretation and critical analysis of rumours.
Adding the word "domestic" is already confusing enough. Is the ex-Varyag not domestic enough even though essentially just the hull and propulsion are foreign? People may disagree with you on that. Adding that on top of a class designation that people may also not agree with just adds to the entirely muddled conversation that recent Chinese carrier discussion has turned into. It sounds like "third Chinese domestic carrier, 002A" is a spectacularly convoluted attempt to refer to a carrier by anything other than "CV-19", which is what that carrier would be.
Well you could call it CV-19, 002A if you want.
For me, it is important to distinguish what that carrier is actually meant to look like and that's where the 00X designation comes in.