https://feedback.unity3d.com/suggestions/change-font-size-in...
http://forum.unity3d.com/threads/when-will-unity-support-hig...
Second threads ask for support for high DPI. It's a simple scale issue, but somehow hard to do it on Windows.
Stuff that should be easy but isn't is a strong indicator of technical debt.
It can also be an indicator that there is noone working on it. It's common to have fix which are relatively easy but noone to implement them.
Or, they just get their priorities wrong, meaning, they're being stupid. Not a safe assumption in my opinion.
> Or, they just get their priorities wrong
Most open source projects have very few or no people working at all. It's common to find bug reports opened for years that were never fixed. They don't have to be complex, just non-trivial.
XNA used to sit in this space, and it was a pretty nifty little game development platform for C#. Monogame has carried on, and expanded the target platforms nicely, but hasn't really made many other improvements, from what I've seen, getting back into it after a few years away.