What's the point in having 3 monitors if not to do this sort of thing? Leftmost is the original DVD release. Rightmost is the HBO upgrade and in the middle is a fan-made version I managed to get a few episodes of. It kind of shows that it is possible to improve the DVD version significantly if the willpower was there.
Seems like they're 4:3 and cropped? The upscale version I have (which I grabbed in 2019 IIRC) is 16:9 and uncropped. I'm fairly sure JMS Intended B5 to be viewed in 16:9, I could be mistaken though.
A full remaster wouldn't be outside the realm of possibility nowadays, but the CGI is still likely cost prohibitive even with the technological improvements since the topic was first raised with JMS. It'd be cheaper and easier to do now than it was back in 2007 etc, but still so many effect shots would require a LOT of work.
Be warned that the HBO versions appear to have some missing scenes. Babylon squared for instance is about 3 minutes shorter, losing the scene where Delenn gets the triluminary and the scene where Sinclair and Ivanova talk about the Flying Dutchman.