We all know that change is coming, and it all seems brilliant until it affects us directly, and it seems like some of the changes Lore is discussing fall a little close to home, as he uses shaman as an example. Spiritwalker's Grace, he says, is a type of casting with movement that they like. It's a cooldown, it's a temporary movement ability, it requires intelligent use. The opposing example is Lightning Bolt, currently castable while moving all the time. The devs don't like that. And I for one agree with them.
When I found out about the Lightning Bolt movement changes, my first reaction was that resto didn't need them. Elemental, sure, they are a bit of a turret otherwise, Enhance not really, but they are melee so have more instants. Resto definitely didn't need them in my book, and they're mindless, there's no additional skill there, no real gameplay, especially when we have Spiritwalker's for those times when we really need to move.
Personally, I agree with the devs that cast-while-moving has become too ubiquitous. Shadow priests have complained bitterly that they lack such abilities, and thanks to DoT snapshotting they can't often reapply their DoTs while they're on the move. But it should be the case that ranged and casters have a penalty for the advantage of being outside the melee fray. The trade-off should be that you can't wander freely around while doing damage, whilst also having the advantage of easy target swaps and a clear view of the battlefield, not to mention being easily able to actually stay in range of a moving target. The trade-off, historically, was that ranged were short on instants and largely had to stand still while they cast. Although it's still true for several ranged, there are others that don't suffer this at all. And that's too powerful.
Hunters, warlocks, shaman, anything with a bunch of instant cast spells, I'd like to see nerfs to all of them. Restore the old balance where the trade-off existed. Ranged DPS should not be able to execute their entire rotation on the move. Lore's follow-up tweet is also very indicative of Blizzard's angle on the whole squish. They're not buffing all the classes up to meet high outliers, as they have before which was the approach that got us into this whole mess. Instead, they're pulling classes down to meet the lower end. And that's a good thing.