What do you feel would make an exporable Ultra Space more engaging to players?
Honestly, I'm not sure. Well, I can think of likely scenarios, but they're not original ones, because they're what Game Freak resorts to literally every time when it comes to plot-significant locations.
The most likely scenario I can envision is that it becomes a Distortion World-esque labyrinth and the focus is on the exploration/platforming - which is still a linear sequence which will have to rely heavily on visual appeal, although given that SM had a style-over-substance approach this will probably be engaging for a lot of people - although I can imagine it also turning into an Aether Foundation hideout of sorts, if more than Lusamine and Guzma go through. But that's essentially a gauntlet of grunts, and we get that multiple times in the games as is.
I think what would be most engaging would be to visit Ultra Space more than once, and make it a combination of things - a labyrinth, a gauntlet of grunts towards the end of the game, and a postgame location. Rather than making it a one-off area of the game, make it something fully integrated with the world, that you stumble into multiple times, with its own dangers and puzzles. Maybe make Ultra Wormholes like the Mirage Islands in ORAS, that you can visit once a day for randomly-generated labyrinths, UBs, or even to rescue a hapless NPC that fell in. Variety is often more engaging.
I realise this will rob the UBs of their "special" status, but it's already been established that they are not Legendary Pokemon, and there are multiples of them - I mean, you can catch at least two of the version exclusive ones, and you see multiple Nihilego too.
I also realise that none of this will ever happen. But if GF want to surprise us, they need to do more with Ultra Space than make it a Distortion World throwback or Lusamine's Dungeon.
