Bamein

Your statement that this is why Guild Wars 2 feels more grindy is... not entirely correct.

First, realize that the skinnerbox theory works with almost all RPGs and stuff beyond, including (if we are to believe the video, Solitaire) However, we're playing an (MMO)RPG, so we should discuss it relative to other MMORPGs.

Now, compare GW2 to WoW, when I played WoW I felt the compulsion to continue way after it's fun. The game is positively built around behaviorism theories. Arenanet consciously went away from these theories and made a more honest game. That's why it's a lot easier to stop content in GW 2 after it's stopped being fun. Me and my friend have had breaks, sometimes days, sometimes weeks sometimes months. We hop from one kind of content to another depending on what we find most fun at the time.

Since we're talking relative to MMOs and WoW is much grindier then GW 2, we must conclude that Skinner Box cannot be a satisfying answer. I would give an alternative one, I would suggest that GW 2 suffers from a similar problem as Dungeons & Dragons 4th edition. The monsters HP are simply bloated. I encountered this both as a player and as a GM. I solved it by mentally decreasing the monsters HP by a certain percentage and increasing their damage by another. The players were ecstatic, they didn't understand why but they found the combat to be not just faster, but also fun exciting and challenging.

Now, when 5 people who are playing Heroes (and yes, all our characters are supposedly heroes) spend a full five min pounding on a lieutenant of a gang (not their leader, no, a mere lieutenant) it can feel a bit grindy. When you mindlessly go around, without any real challenge and start discussing dinner plans next Saturday while pounding a boss, it can feel a bit grindy.

melee doesnt suck, players suck at melee.

Don't blame game mechanics for your inability to melee