A questless playthrough has been a thing for years. A questless playthrough is a solo playthrough (needs quests to get Companions).
As for the Hunting Bugs oddity, I think that was first noted around version v.09 something? I --think-- at the time the issue was deemed rather tiny. The mimreks give very little XP and as you gain levels, it becomes zero. So not really game breaking.
Just tested it today, and it seems as long as the Hunting Bugs quest hasn't been started, you can still use the pit to get unlimited low-level bugs. The self-spawning ones will give zero XP the first time they're killed, but the ones that pop out when smashed give normal XP.
Also, I used the new Storymode to create a test charcter. The new regeneration is insane.