Greasy Fork is available in English.
Moves the controls under the video and makes the UI look like it was before august 2015
I've rewritten the script (to make it a bit more readable), so there is a small chance some of the issues have been (accidentally) fixed.
Can you give me a link to a script that blacks out the background (that has the issues)?
The issue with skinny players should be fixed in the new version.
Scrubber issues
Serious issues lately with the new scrubber line and button that indicates where in the video is being played. If you use any script that blacks out the background, the previously visible red line now disappears and the button has turned into a black square. I've fiddled with the settings to bring back the old white button instead of the square (however, reducing the size of it massively, as it ends up on top of the video), but this is far from what it used to look like.
The video control panel height you have as 41px is actually exposed in my black script with its white borders as needing 40px to have the bottom border visible.
There are also weird transparencies with disappearing controls (in other words, this script doesn't work) when YouTube videos are popped out on other sites with the controls hanging over the video.
When videos are skinnier than 16:9 widescreen, there's now an issue of videos rising to the top of the video player (usually) rather than being centered vertically.
YouTube has clearly been regressing the quality of their scripts again. Playlist scrolling using arrow keys is all messed up (NOT the result of my black background--I've checked with everything disabled), as is a non-transparent box that appears over Playlist video times if you change the background that the only way to get rid of seems to be element hiding the menus on the side (my script skills aren't advanced enough to figure out how to make a specific element transparent). Things have changed and recently. This isn't your script, though. The video controls have been redone in the last week or so.