Well, to bring it in to HD and have it look decent, it'd require more than just remastering it. It'd need a whole set of new effects, as was done with TOS-R. And if that's the question, then yes.
A thousand times, yes. I've often thought of doing some scenes myself just as a personal project. Especially after The Lost Tales showed how damn pretty it would be (scroll down on this page for some HD screencaps
There are two main problems: The first is money. Babylon 5 is not, and never will be, Star Trek. It's doubtful Warner will ever decide to pony up the money to have somewhere between 110 and 130 or so (depending on if they decide to do the movies and Crusade as well) get their CGI effects completely redone.
The second one is that, while they already have digital HD copies of the live-action footage that they made for the DVDs and Sci-Fi Channel reruns, they may not have it for any live-action shots that included special effects (from set extensions to CG aliens to PPG shots). Babylon 5 hasn't had the best luck with the archives (many of the original CG files were lost in storage only a few years after the show ended, and I believe rats got into the original film from "The Gathering"), and if those shots are unavailable, then the whole project would just be a waste of time, because you'd still be stuck with a massive quality loss in shots combining live action and visual effects even if anything that was pure live-action or pure CGI looked perfect.