I'm A Banana
Potassium-Rich
In other words, either go generic or go flavorful, but whatever you do, own it.
A fair argument.
Bingo.
My personal sympathies lie with "flavorful," because there's a much meatier RP hook to sink your fangs into if you are a "Knight" as opposed to a "Defender," but that means the complexity dial is at a higher level than subclass: you'd tune your simple Knight to a more complex Knight in a different place than you'd pick between Knight and Gladiator and Myrmidon (or whatever). Which isn't necessarily in line with what WotC's goals are. Just in line with what MY goals are (which is to be able to have a meaty RP effect from my choice of subclass, and worry about mechanical complexity on a character-by-character or table-wide basis, rather than within the class structure).