1 ultimate instead of 2 ?

[SaberMaxwell]

An endurance challenge would be interesting, but even Ultimate is already pushing up on being an endurance challenge already. On release ucob was closer to 18 minutes than 15, and iirc uwu was ~16 minutes or so.

The issue with "just make it longer lmao" is even in Ultimate you see a drop-off of mechanical complexity as the fight goes on. Compare Golden Bahamut (realistically just tankbuster raid buster dodge 1 mech repeat) to Nael or even Twin. Or Perfect Alex to Living Liquid or Brute Cruise. It wouldn't be as simple as "just glue two ultimates together" because mechanics would by nature of SE's establishes flow of an Ultimate, only make it easier from there. That or they really do follow up P.Alex with Twin (ok, Twin might work but Nael?) and subject already exhausted players to a mechanically complex situation and I think you'd get more frustration.

I think an endurance run going beyond 15m could be an interesting concept. Maybe make it wave based survival in an endless (so, 90 minute survival mode), with randomized mobs including some bosses included? It's a concept at least.