Needs a grifball style playlist(swords and relics?)
Needs an infection game mode(thralls as infected, each guardian gets a standardized shotgun/hand cannon).
Huge 50 person PvE events where you must defend the city walls from a 20-30 wave invasion, level increasing with each wave.
Weekly/nightfall strikes should be new strikes every week. That way it's even more challenging so we have to make strategies on the go(harder to cheese).
Just some of my ideas