Maybe ditch the filter and just concentrate on the dtm/lumen side of hdrI think that would be sensible from Epson. Maybe try and tweak the cinema filter so it doesn't lower the light output as much also. Then they would be in a more competitive position for HDR.
4K would require a completely new design so that may not happen?!? Not so important anyway in my opinion. Resolution isn't so noticeable in all the comparison's I've seen and not the determining factor for image quality.