My issue isn't with the letterboxing per say (I play a lot of games at a 2.35:1 ratio on a 16:9 monitor anyway) but the fudged way it's been implemented. True 21:9 monitors and 3 screen set ups don't handle this very well at all and seeing as the past id Tech 5 games did (Rage needed a bit of tinkering) I don't think this is a quick fix. That and because it was a consideration from the offset where UI information resides in both the upper and lower portions of the screen it's never going to be perfect. I'd keep an eye on WSGF for solutions.