Nah, my concerns, such as they are, are just about keeping the number of base options to a manageable number of broad archetypes - perhaps a dozen or fewer. Multiclassing is, in theory, a way to allow greater character diversity within a system that has a small number of base archetypal options. Though, I would really prefer more choices within each class, instead of having to mix different classes together to achieve this diversity, which in my opinion defeats the point of having a small number of broad archetypes to begin with.