Hey there @WhiteTigre,
Incremental patches that contain small bug fixes (such as 1.5.8) are generally released each week on Monday. Recently there has been a lapse in weekly updates due to the holidays, and the impending release of Update 6.
Some of the bug fixes that seem like they would be smaller are being resolved by larger system updates and are not able to be released in an incremental patch. This is why quite a few fixes are being rolled into Update 6. That said, the patch notes for Update 6 are by far the largest we have ever written, and we look forward to sharing them as soon as the patch is ready for PTS!