I’m not using WavPack nor am I likely to use WavPack in the future, but looking at their webpage it does seem that there should not be any reason why Roon couldn’t include support for it. It’s open source, multi platform and avoiding patented stuff.
Then again, if only a few people are interested in it, it might not be worth the effort unless everything worth doing is already done 
I actually have no idea how big of an effort it would be, but I assume it’s not a big thing.