Playing with bars on top and bottom isn't great, either. See what I did there?
The point is, past is in the past, present is here and we've yet to see the future. It's a common problem with older games; there are either various display issues or the game doesn't work at all. It is NOT possible to crop artwork well enough to fit both 16:9/10 and 4:3/5:4 aspect ratios, you have to chose. The only thing left is preparing a build with art assets for both, but this means almost 2x the size of stored graphics... and a lot of work, including hugeee production costs. It's quite peculiar, but I've rarely seen studios, actually archiving all the production assets, which is mindboogling. Most often, they get lost with time or various copyright/legal issues prevent them from being stored/re-used (especially cases, when you work with freelancers and they aren't working on a plain contract, but more of a contribution). most often, these change with time and aren't able to work on a reneval version anymore, or take their work assets away with them, meaning the chances for a possible redraw/corrections become slim.
I personally find RURUR more interesting and better than Dies or KKK. Why? Dies Irae concerns topics and subjects which are - in fact - truly exotic to most japanese (and us), while KKK is a folklore tale reminiscent of ancient japanese classics and something most western players (not talking about weebs here) will have a hard time getting into. RURUR is basically a semi-hard sci-fi adaptation of The Little Prince, only for adults