Spellcasting power is at best tertiary to this discussion. There is a caster/martial divide, though it is much smaller in 5e. However this topic is talking about the power that this feat gives some martial characters. That increased power isn't really relevant to the topic of the caster/martial divide and to use this feat as a "fix" to that divide is incredibly problematic as it does nothing for many martial builds. At best this strategy would further weaken classes like Monk, Rogue, Ranger, or TWF.