Since remastered versions of DS9 and VOY aren't happening any time soon, I think the next best thing should be a SD-BD release, kinda like how Discotek Media are doing with some old anime titles
Higher bitrate isn't going to magically get you higher video/audio quality. There's a point of diminishing returns. You just get a larger file size. For SD, anything more than about 2.5 Mbits is visually indistinguishable.