Last week, Syp brought up the ability to move while casting as part of a list of things he thinks every MMO should have. While most of the items were minor quality of life features, like AoE looting, his comment section got blown up by people who thought moving while casting was the worst idea ever. He even went so far as to post again, expanding on his reasons for including it.
I am firmly in the move-while-casting camp. After years of being frustrated by my inability to move while casting, I just learned to accept that I needed to stand there and take it while trying to out-DPS my assailant, dumping as many talent points as possible into interrupt mitigation. I was so far gone that one fun pugger said, "Oh I see, Hazel is an in-your-face finger-wiggler." I was so used to mobs (and players) attacking me directly that I didn't even move back when I had a tank to divert attention away from me. Rift and SWTOR have similar mechanics, though I played more melee style on my Cleric. And combat in SWTOR is a faceroll. Then along came TSW and GW2. (Sounds of Gregorian chants: "Aaa-ahhh") I don't want to ever go back.
While trying out MoP recently, even the shaman I used—with a mostly melee abilities—felt handicapped when having to settle down to cast a lightning bolt or something. As a caster in previous iterations of WoW, I got stun-locked too many times by a rogue coming out of stealth to buy into the "melee have to move in close, so ranged casters should have to stand still" excuse. The warriors might have a little more justification to cry about moving casters in that context. From my perspective, it certainly never felt balanced.
TSW and GW2 are both balanced to necessitate dodging, and moving while casting. Those who stand still usually die. I'm also not talking about continuing a cast through a drastic move like a manual dodge mechanic, which still interrupt casting in both games. I'm talking about casting while simply running (or walking).
You could say I never learned to play my clothies properly. That's great, until you think about the DPSers (or even the tanks) that blame the healer, when they the ones moving out of range or out of sight of a long cast heal.
The old-school arguments about things being correct the way they were—the "if it ain't broke" argument—forget or ignore that almost everything in a game is a design decision. Balancing this or that class against another can be done a bunch of ways. Tell me this, old-schoolers: was there ever a game where the casters dominated so thoroughly that the devs made the decision to nail their feet to the ground?