Sequencing might become cheap enough to do that, but our understanding of the functions of the different genes is so lacking that I don't think a lot of meaningful data can be extracted for most studies' subjects.
I don't think we necessarily need to know the function of the genes in order to create a participant matching paradigm that is better than what is being employed currently. For example we can get a more precise snapshot of ancestry using sequencing than simply relying on self-reported 'race'. Also I don't think it needs to be a perfect match; simply stating that controls matched case participants within X percent ancestry would be a useful statistic to report in the methods.