Hi, I only found Voukoder recently but I'm already a big fan. The only minor annoyance I have is that you can see the encoder parameters in the advanced options, but you can't edit (or copy-paste them) manually. It is an issue for me for several reasons. First, I'm more used to internal parameters names like "keyint" than "GOP size (frames)". Second, if I ever want to tweak some of the values, it takes ages to find and edit them in the above list, whereas you could change them nearly instantly in the Advanced Options textbox. Please consider making the command line editable, as it would make the plugin infinitely more enjoyable in my view.
As for other suggestions, I'm not as familiar with the plugin's inner workings to suggest something definitively, but it would be great if we could use separately compiled libraries like SvtAv1EncApp.exe, x265.exe, or ffmpeg.exe to be able to update them manually on the fly, without waiting for Voukoder's dll update. Sorry if I'm missing something or if it's an impossible proposal. As I said, I just started using it recently and haven't had a chance to study this.
Another down-the-road feature ideas would include making (save/edit/rename/delete) profiles within Voukoder's own window (low priority, since you can save presets in Premiere) and adding command line parameter names in the tooltips, so when you hover over something like "Adaptive QP Level: Deltaq pred. efficiency", you'll see "aq-mode=2" listed at the bottom of the popup. The latter one would be very useful, since it took me two encodes to realize that your AV1 "Preset:Medium" refers to "preset=4", and not "preset=5" as I'm used to associating it in other programs like StaxRip.
Anyway, I hope you find at least some of these suggestions useful, and thank you very much for keeping this invaluable piece of software alive.