If you have any problem or suggestion please post them otherwise its never clear to the developer, what exactly user wants.

Please provide more information on:
1. Provide the url for the sites where download is not being picked up by XDM. Even for videos, you can configure XDM to take over the video files directly.
2. Pasting the url in refresh link is there, you can paste the url by ctrl+v, popup menu for every textbox will be provided in next release.
3. Again for the download session, please post the url as this things needs testing.
4. What do you mean by clunky user interface? The look is exactly same as XDM 2016, at what point you experience the slowness?

Now whay it needs Java?
XDM 2018 is written in Java but you do not have to install Java to run it.
XDM was ment to run on every OS, so there was a .NET version for Windows and Java version for Linux and Mac. Its rewritten in Java because I was facing problem maintaining two versions.