The reason why casts come up in this discussion is because if someone wants to argue that 'positionals' are not intrinsic to Melee DPS, then they also have to concede that 'casts' are not intrinsic to Magical Ranged DPS. It just so happens that in this game, Melee have positionals and Magical Ranged have casts and they are viewed as a part of the 'identity' of their respective roles in this game.

I also think it's worth mentioning that positional elements aren't exclusive to this game, either. Positional attacks in RPG games are as old as D&D's backstab, and there are other MMOs that have incorporated positional elements before, Lost Ark being an example off the top of my head. In fact, some of these games have physical ranged positionals too. It's really just a way of adding an additional spatial/positioning consideration to gameplay.

If you want to have a role-based system in an MMO, it's important to preserve role identity. One of the big problems that we've seen in support roles is devaluing them by removing key gameplay elements. We have tanks who have diminished positioning and mitigation responsibilities and healers who have diminished healing and mitigation responsibilities, all in the name of 'accessibility'. We don't need to bring that across to DPS.

I think the dev team have made both Melee and Magical Ranged DPS very accessible to players who want to play those roles for aesthetic purposes but have no specific interest in self-improvement. All that people are asking for is that you also allow some room to preserve skill expression on these roles.