I get where you're coming from. A trade-off sounds nice in general, but using the beam sometimes feels off. I just posted about this some minutes ago. It takes more time to actually dispatch enemies that are usually a one hit uncharged. Like bats for example.
Due to this I more often than not smash into minor enemies, that remained undestroyed in the beam for a while. Especially if I fire the beam mid dash-jump. I get that the hitbox is a wee bit smaller than one from the previous charge level, but if a minor enemy is directly in the beam, that usually is just destroyed by one normal X-Buster hit, it should disintegrate instantly, no?
On a different note: The original X1 had at least the same damage value between charge stage 2 and 3 and X3 had one point of damage more on the last stage then the one before. So technically it would be more true to its source material. But I get that this might feel like a stretch. x"D