More likely is that they have finite resources, and they are focusing on Win 10 driver model which is different from the Win 7 driver model. NVidia also gets blamed for the exact same thing. Keep in mind that the 280x is a essentially a rebranded 7700 which was 2 years old already when the 280x was released in 2013. The 280x also does not support freesync, so there must be some sort of significant architectural differences. I am pretty sure that AMD is more focused on their newer hardware like the 480, and the issues facing it.
I suggest going with the older faster feeling driver. Users don't really need to upgrade their drivers if everything is working ok. If you did need the newer drivers for a particular reason, then you will have to wait till the next driver and hope.