First of all, many thanks for all the hard work. I am preparing a switch to Ubuntu MATE when I upgrade to Ubuntu 18.04. There are many desktop environments out there, but they all have fundamental problems somehow.
If there is one issue that really needs attention, it is the extremely thin window resizing borders. I myself have read all about it, and I got used to Alt+Mouse resizing to the extent that I miss it dearly when I am not using Linux. But this is a problem for many other people.
I often try to convince other people that Linux is the way forward. I normally face stiff resistance, especially from non-techies. When I expose somebody new to Xfce or MATE, the first thing they notice is the strange taskbar layout, but I can fix that in a couple of minutes. And then, they tend to discover that they cannot resize windows. Many people just cannot move the mouse or touchpad accurately enough to grab the very thin window resizing border.
I am talking about a default installation of Ubuntu MATE 18.04. My display is not even HiDPI. This is not just a single issue, it's a glaring symptom of neglect. It happens to everybody, every time. Since years. It has been discussed everywhere. There are blog posts about this for Xfce and MATE. I often hear comments from new users along the lines of "this is why people don't use Linux".
Choosing another UI theme is not a good solution. A theme is an all-or-nothing approach, and there may be other things you do not like in the new theme. Or that theme may still fall short if you do switch to a HiPDI display. Besides, who wants to test several themes until you find one with fat window borders? I am a developer, and I am not prepared myself to edit theme files which may get overwritten by the next system update.
On Microsoft Windows, you just adjust the window border size to your liking. There is a bug in Caja suggesting an invisible frame around windows to make resizing easier. I am sure there are many other suggestions and discussions around. But nothing has happened yet.
I would not underestimate such usability issues. It quickly drives people away. A successful user base cannot be made of just geeks.
Is there a reason why this problem has not been addressed yet? Or is this truly another flagrant example of open source UI neglect?