Firstly, and most importantly, the cost will be lowered. As the blog states, "Items upgradable by Valor now require 250 Valor to upgrade per 4 item levels, for a total of 500 Valor for 8 item levels per item. This is retroactive to all items that use Valor." This is a massive discount from 5.1, and is there in an effort to try to avoid the feeling of having to worry about spending valor to upgrade an item, betting against yourself for an upgrade.
With the new lower cost, the aim is that players can use their valor to upgrade items without worrying about using up a huge chunk of the currency they could be using to get new gear. The flipside of this is that valor will remain valuable to players, for a limited time at least. It will be possible to upgrade two pieces by eight item levels every week, if players cap valor.
No comment was made in the blog, however, on the new Thunderforged items, and whether they would be upgradeable. These items are already six item levels above the usual, and upgrading them by a further eight item levels would mean that they could be best-in-slot for some time. Whether this is a good or a bad thing, we're not sure. It would add weight to the philosophy that Blizzard wants players to be excited about loot drops from early bosses, but would such a huge ilvl gap be problematic?
Justice gear is also upgradeable, at a higher cost to reflect the increased rate of justice point gains in patch 5.2, but still lower than before. 5.2 Justice items now require 750 Justice to upgrade per 8 item levels, for a total of 750 Justice for 8 item levels per item.
For clarity, items originally bought with valor, conquest, honor or justice -- and this means only season 12 gear in the case of PvP items -- will still be upgradeable with the currency it was purchased with, even though it's not current tier or current season gear. This is in line with the way the PvE currency conversion was carried out at the patch 5.1-patch 5.2 crossover, but less so for PvPers. It's likely that this is to discourage the spending of conquest points on upgrading season 12 PvP gear, given the better options available, unless you have season 12 T2 weapons.
What do you think of the altered system? Are you glad it's gone from PvP? And will this mean that players will end up with leftover valor at the end of patch 5.3?