I see, though it would have been better to simply implement 3rd tiers and ignore 4th tiers. That way, classes would have been more balanced. It feels weird that certain class trees have more promotions than others.
On the contrary: "max stats are tied to character" Thus, overclasses are, as far as we know right now, worthless from a gameplay perspective. Not to mention the fact that the game is too easy to warrant them in the first place.
"overclassing isn't a necessity" already states that they are superfluous.
Yes, I agree, the main and only point of these classes right now is aesthetics. However, people are different. Some value gameplay more and some value aesthetics instead. I'm in the former group. Consequently, the classes don't appeal to me. This may change if we get Apotheosis and more information regarding the classes.