If you're making a claim based off of HP scaling, then you should also make a claim based off dps scaling. If Cecil as a Dark Knight is definitively a "dps", then he should be doing more damage as a Dark Knight than he is as a Paladin. That clearly isn't the case. He has less stats across the board. The reason why his stat scaling is weaker as a Dark Knight is because you're expected to climb Mount Ordeals at the level 15-20 range as a Dark Knight and come down as a level 1 Paladin. You can think of Paladin as being his "job upgrade", similar to the Fighter -> Knight transition in FFI. So I don't think that argument really holds up.