Bungie needs to stop putting so many resources in creating content and activities that are temporary and then get left behind, each and every season. This mainly applies to their PvE activities. We have Escalation Protocol, Blind Well, the forges, Reckoning, Menagerie, Vex Offensive and now Sundial.
They need to develop something that is sustainable, something permanent, that can easily be amended, improved and upgraded as time goes on. It's just such a waste to reinvent the wheel and start over every season. It's horribly inefficient. It's not the first or second time I've said this either.
The Menagerie is the most fleshed out and most robust of them all. The Leviathan, being so massive, and being such a profound destination, lends itself to having more and more sections and bosses added to it. It also has fantastic loot mechanics, arguably the best ever in the entire history of the game. Plus, Calus giving us more to do and more challenges is in congruence with the lore and ongoing narrative too.
There as to be someone at Bungie who has had the sane idea.