This seems like something that would be less of a full update and more so a feature that just needs to be toggled on? Because I can't imagine this much of a load bearing issue.
But the ability to select between our kinetic and energy weapon slot as the primary weapon when viewing your charcater in the menu, cut scene, crucible, etc. Perhaps this can even extend to your equipped weapon you initially spawn with when beginning a new activity.
I dunno, maybe I'm crazy but this feels like a simple thing we should have had the option to select since the beginning. And I don't recall seeing anything about it before.