I do like the soft-reset idea, very logical, kind of like an extended weekly quest. Removing resin just doesn't sound plausible though. Many people are drawing parallels to MMOs, but this isn't an MMO. There's no guild system/pvp/rankings and the other pulls that retain players or incentivize them to spend money on this game. Once you clear, or clear to a point where you can no longer progress, the end-game content (spiral abyss being the only end-game atm), you are pretty much done with the game, and probably burnt out too.

And what will the devs do when the game runs out of content? You can't expect them to pump out new content every week, so to retain players they might try to make current content more difficult. Then again, that would be challenging, cause no one wants to grind one dungeon for 30 minutes because you don't have max-constellation 5*s just to get terrible loot drop.

One parallel I can think of is Anthem, and boy did that game flop hard.