This makes sense in many ways; the primary focus of the "grind" should be acquiring new gear across all slots, not making minor incremental changes to the gear that you've already seen dropped. Valor points also will continue to be useful in the mid-patches with this philosophy (5.1/5.3), versus just becoming something you've got and are never going to use, which often happens during the later end of a raiding tier.
@champlain1635 Our plan at this moment is upgrading only for patches without a new raid / PvP tier. That design could change.- Greg Street (@Ghostcrawler) January 5, 2013
We're assuming here that Ghostcrawler's note will just apply to patch 5.2 gear, and not the total system. It would seem quite odd to just switch off the entire upgrading mechanic all the sudden.