I approach this topic as someone who mostly played CCGs prior to ESO, especially Magic: The Gathering. In case you aren't familiar, MTG has 5 colors, each with its own specializations, strengths, and weaknesses. And certain colors are better at fighting other colors (ex. a red burn deck is gonna struggle against any life gain, which white specializes in, so there is an inherent, but not overwhelming "rock-paper-scissors" quality to the game's balance). And while the analogy between MTG and ESO is not perfect, it at least illustrates a point.
That is, when all elements of a game (color in MTG, classes in ESO) are balanced to complete equality, we lose some of the fun and unique identity in a given element.
For example, consider DK's wings. DK is the worst class for mobility (perhaps tied with Templar), so to make up for that lack of mobility and range, they are given a skill that hoses a different kind of play style (i.e. ranged players). And while I don't complain about specific nerfs/changes, I'm not sure I like the idea of having all classes being more-or-less equal. In other words, I think it is a great gameplay element to have certain classes with inherent "edges" against other classes, even if that just means that certain classes are tankier, or more adept at damage or healing.
Do you agree? Should ESO be balanced for balance's sake, or should there be this kind of "rock-paper-scissors" quality to class interactions? There are obviously pros and cons to each, and I ultimately like the idea that I can roll any class as any role, but I fear that "leveling" the classes to the point where they don't feel as unique and specialized is going to make the game less interesting in the long term.