Except in the case of the FSS/DSS there are ZERO grounds not to change it.
EXCEPT for the one, most important, overriding ground, as stated by FDev: "It's not what we wanted."
Sorry if that's inconvenient for how you want to play, but it IS their game, their vision, their product. What they want comes first. What we want comes second. If what we want aligns with what they want, it is more likely to be implemented. If it's not, then it's less likely.
There are numerous flaws in the implementation and design that are undeniable on the whole.
Not so sure about the quantity, but I will not argue against improvements to the system. There are a number of reasonable improvements that could be made - scroll back a few dozen pages, I made my own little "if it were up to me" post here in this thread.
The 3.3 exploration changes arguably have had a net negative result on ED as whole IMO and the opinion of others but that could have been avoided if they had not removed the ADS in the first place.
Arguably? Ok, I'll argue. I feel the opposite is true. I would NEVER have made the trip I have been on since the 3.3 launch with the old systems. It was pure, concentrated, distilled crap, with absolutely nothing enjoyable about the tedium that required NetFlix to endure even a short trip to unlock Professor Palin. Now I've traveled nearly half-way around the galaxy's rim, and I'm still going. I would argue this has had a positive effect. Now, I'm not qualified to provide a NET effect, nor are you, as neither of us have any actual data as to what percentage of people find the new system an improvement vs. the number of people who do not - and you're not particularly interested in those who do, as this is contrary to your agenda.
Moving forward changes to the FSS/DSS are essential to the QOL of the product as a whole. FD need to realise this and plan to address it as a matter of priority, not necessarily immediately but perhaps as part of (or after the release of) the next major expansion.
Again, I will not argue that improvements and QoL enhancements are necessary, they certainly are, and it's a money-bet Frontier is more than aware of this and many other areas in need of improvements and enhancements. As to how they prioritize, that is not for you or I to decide. I get that we all want what we want, right now, screw anybody who wants something else, they mean nothing to us, only what we want matters.
Fortunately for all of us, Frontier knows a bit better than we do, and will prioritize what gets done and when. Let's see how this relates to Exploration. One QoL enhancement I would love to have would be the ability to collect samples and specimens - core samples, biological specimens, gas samples - and we have things like Planet Surfaces to take core samples. We have biological POI's and gas giants with various forms of life, as well as space-based life forms that could be collected. We have atmospheres to take gas samples. But we don't have the ability to enter an atmosphere yet. We have limpets that could potentially be used to collect samples as well - we use them on Thargoids already. To implement these kinds of systems and improvements, you should be able to see that there a number of other things that have to be done first. The priorities start defining themselves.