This isn't a complaint about something new - it's something that's been an issue from day one and, IMO, is likely a major reason why the game struggles to retain players despite its many positives.
This is it in a nutshell: Class design more closely mirrors an on-rails RPG experience while overall game design more closely mirrors a sandbox RPG experience.
I've long felt they over-compensated for "too much imbalance" in GW1 by over-engineering classes in GW2 when the game isn't really designed with that in mind - utilizing an end-game of horizontal growth and fashion wars. While everyone seems to love elite specs (probably just because they've been to date the only significant offering for class expansions), my opinion is this was conceptually the wrong way to tackle ongoing class development - it maintained and even reinforced the on-rails approach while the game was simultaneously moving in even more of a "do whatever you want!" direction. This is a bad dichotomy. A sandbox RPG experience that focuses on horizontal growth needs to unshackle these kinds of constraints and allow players to experiment in all kinds of ways. This is a big part of the reason why, in my view, Path of Exile ended up spiking in popularity after Diablo 3 was sort of a letdown.
So what does Anet really need to do here? My view is that it's time for a system refresh - can the notion of "elite specs" and go with a much broader mechanism to continue expanding classes. There are really all kinds of ways they could do this to expanding weapon types, expanding weapon skills within weapon types, having loadout packages that resemble elite specs but are more balanced with core abilities so they can be mixed-and-matched, and allowing players to level multiple classes on the same toon.