Thanks for your feedback @jpegmasterjesse!
-Would love if, when a clip ends, spacebar would restart the video by default.
Okay. Could be done somehow, I think.
Edit: done. But the clip needs to be longer than 1..2 sec, because switching the debayer algorithm to playback setting + jumping to first frame needs time, so you'll never see the first frames. It still works better using X button.
-When using MLV App to preview/delete footage, it's a bit of a chore. You can't delete a video if it's open in the file browser. You have to delete it from MLVApp and then remember the title and delete it in explorer. If it's possible to delete the actual file via MLV App that'd be ideal.
Already done.

-Re-sorting videos based on name/date/ect would be nice.
Puh. Could be possible, but will be a hard job because of internal realization. We just see the infos from the current clip and just filenames from other clips. So there is nothing to sort but the filename - and this would work exactly one time and never again.
-Maybe a render-queue would be nice? Since you can't work/queue up additional videos while rendering, there's a video of memory and juggling involved once you've finished working on your videos.
Unfortunately 100% impossible with current concept. We would have to rewrite the whole GUI. And even then rendering speed and export speed would drop by 50%, because we then have two tasks at the same time. So this would be extremely slow.
A star rating or color label system could help with this too.
Yeah... myself, I would like to have that, but don't know yet how to realize it... not impossible, but I want to have it in a nice way, and we have to think on a couple of existing presentation features.
-This is a long weird one. I recently acquired a fun little tool that magic lantern users might be interested in. It's called a tourbox, and it's essentially just a handful of buttons, knobs, and dials that currently is well-integrated with Photoshop but can work with any software using keyboard commands. Right now I can't really use it in MLV App because there aren't any keyboard commands to assign. If MLV App had something like Mlrawviewer had with changing color bance (4 and 6 changed blue value, 5 and 7 changed red value, ect), that could be a nice efficiency. Or more simply, if there was a "next slider" command and highlighting each slider allowed for alteration with keyboard commands (like up or down arrow), you can go down the list and use your dials to change values.
On Windows this should be possible with Tab and Arrow left/right, isn't it? I thought this is Qt standard functionality (at least on Windows). Edit: works.
You can't connect e.g. a mouse on this box? This thing has enough CPU power to render frames?