I think we'll see about its balance once people adapt and change their strategies to take it into account.
Energy was, formerly, a bit of an underdog. Not as fast at finishing as Physical, and not as brutally effective as Heat.
Lets see how this will change the meta

As always of course, a close eye is kept on these new weapons and if we find them to have a negative effect on the gameplay/balance, we will take action.
But yeah, takes more than some days to know that. Right now, I reckon many mechs simply arent built to survive energy mechs as they're not so common.