At this least, this could make monitoring the PTR process exciting as we try to figure out what Blizzard may add and take away. In addition, although Blizzard has said that they don't plan any major classes changes, this might mean that we can still hope for the tweaking of some abilities. Nethaera's already made it known that she's watching a few well constructed shaman threads about the changes to the class or lack thereof, at least.
In other news, Bornakk has updated his post on International PTRs with the news that Blizzard now plans to make the servers accessible over multiple regions for 2.4.0 only. So unfortunately, if you were planning any raiding or PvP tourneys to see which region reigns supreme, all bets may be off.
With this new progressive testing announcement, we'll be sure to keep an eye on the notes for you and tell you as soon as we see any changes, so keep us in mind here at WoW Insider for your patch news needs.