Yeah i've dealt with a HDR stuff before, and the main thing you come back to is: its hard to make HDR content. While it is of course better quality, i can make a nice LDR cubemap in like, 30 minutes. Where as HDR cubemaps require expensive cameras, hours of time to create, etc. That was one of the biggest problems with the marmoset engine, all the lighting came from HDR cube maps, but it was near impossible to customize them or create content from scratch.... Maybe support different modes for HDR/LDR cubemaps?
As far as the UI stuff, i may have been using an older version, i think i got v1.5 off of another forum, havent had time to test out what you've posted here so ignore it if its changed since then.