First, I personally resent your statement about the community here and users hacking and improving. I refer you to one of my earliest posts here in the Delta forum, or any of the half-dozen modifications I documented in the K8200 section. I am only one of many customers who contribute to the discussion here.
Second, I am not disagreeing with the need for bug fixes for the Delta, nor am I arguing against doing so if you wish to. I have noticed one or two anomalies that I suspect may be Marlin bugs. But I am not just going to blindly apply new firmware versions, hoping that they will magically cure my woes.
None of the flaws you have listed in the Delta are firmware issues. If you are asking Velleman why they haven’t yet updated to a new Marlin, I am asking you what value, specifically, you expect the new Marlin to deliver?