WF for me retains its fun on pretty much just one level now: sheer murder. The new mods, the new 'frames, the "new" weapons....all just there to stop the game from basically being an arena murder simulator.
There's still some fun to be had optimizing your Warframe and tweaking each weapon's set up to its top performance....but at the top level WF just doesn't deliver a variety of challenges to keep that fun train rolling down the tracks. The Arch-Wing update is going to be yet another distraction from WF's core issue: its gameplay hasn't changed at all. Nothing has been added that has elevated it from a run and gun shooter. Better stealth, better missions, are all supposed to be gateways into taking WF's gameplay to the next level.....but each new event is just a rehashing of what we're already doing, and the game goes nowhere. Arch-Wing is just going to add another disconnected facet of the game, instead of making the running, the shooting, the level navigation, better and more meaningful. I like WF still but it feels like it's been in stasis since I started playing it. Clan Halls, Kuboro, Melee 2.0, Arch-Wing, the half dozen new mission types....all of it has felt like a distraction from putting the last pieces into the core gameplay that complete it.