Now, we have some more info about this and as per our sources, GDR2 may add support for 2K resolution display and Snapdragon 805 processor. Seems, Windows Phone 8.1 has support for only two new resolutions QHD 960 x 540 and 854 x 480 and up to Snapdragon 800 in processors. But, if the tip has to believed, next Windows Phone 8.1 Builds are already getting tested with 2K resolution display and Snapdragon 805 support. We caught one such device on GFXBench sometime back.
Though, it seems better hardware support may be pushed much before with GDR1 update as well, if there are change in plans, due to vendor’s pressure and now Microsoft has many of them.