He isn't talking about choosing a class and then always getting it, he is talking about choosing a weapon "in" a class and then, when selecting this calss, getting this specific weapon.
It shouldn't be that much harder than placing some kind of cookie somewhere so the game remembers your choice and makes it default instead of the weapon on top of the list.
I can't see where your problem is. The suggestion is good. Sure, its not much work to click once (twice, actually) everytime you choose a class, but why not do away with that?
Whether it is too much work isn't yours to decide but Ramm's.