Yes, deso will be broken, especially against energy mechs with low health. And the absence of energy cost allows you to focus more on res and health, which is why most energy free heat mechs are very tanky, except against energy free physical mechs. But go ahead, buff heat when it's still perfectly good with volcano mechs and now heat huggers with swoop, and just leave energy as the worst element. Yes, such a great decision.
And if you say you want every weapon to be meta, why not buff emp or valiant? Or I don't know, hell, even frantics. That's all you want right? Something aren't meant to be meta, what don't you get?