March: Taken PoE. 320 Light recommended. Variks Armor / Weapon Cores at 310. Challenge: go flawless. 320 guaranteed drop.
Shadow of Veils every where.
April: SRL with Reef rainbow road
May: TAKEN CE. Crota's spirit sword logic blah blah, retcon the asshole in somehow. 320 Light activity. Challenge: everyone needs to hit him with sword at least once. Balcony ledge geometry made narrower so you can't stand there anymore and ignore everything like we do now.
June: Destiny 2 Alpha hype
July: Bungie says fuck it, 320 Light Taken VoG because why the fuck now. Get your FB. New Atheon drains your super meter during TV and keeps moving instead of standing still so he's hard to crit. Challenge: don't use any heavy ammo in the entire fight.
August: one month to go for Destiny 2, this game is finally dead. 2 new playlists as a send off: no super Iron Banner and Mayhem Vanguard Strikes.
This is a quickly thought out plan of fun stuff which could keep the game fresh without distracting dev resources from the sequel. It's not so much that they can't give us new stuff like this, it's just they're not interested or don't agree from a design standpoint.