I just tried this mod after seeing it pop up in the updates; I like it but I think a bit more work on this front is needed .Sliders are too dark and also have a "disabled" look to them, and Red buttons such as Exit/Cancel as well. Generally, all of the yellows/oranges Factorio uses (mouseover hilighting of buttons for example) become too dark and muddy with this imo. Sliders, checkboxes, highlights, etc.
Yeah, personally I found the modded research menu particularly depressing with its drab yellows and greens. I think I just got used to it too quickly and now in retrospect it looks rather gross and 'muddy'. A good dark theme should always seek to have a very clear contrast between different elements and their states.
For 1.0.2 I have applied the same logic that I used for the green buttons and elements and have extended it to elements of other colours as well.
I'm very happy with the way everything looks now, the colours that should pop out now do and I like the way it all looks. If there's any more inconsistencies you spot or if these changes aren't quite there yet, feel free to mention them here. :)