This is awesome... Why couldn't we have this?

[Felis]

Leveling was almost exclusively done through guild leves. Someone correct me if I'm wrong, but initially you gained six allowances every 30 hours or so

8 battle/gathering leves and 8 crafting leves every 36 hours (not building up if you missed to do leves before the next leve reset).
It gave the game a "3 days rhythm" feeling:
Day 1 - leves
Day 2 - leves
Day 3 - do whatever you want (no new leves until next day)

However, there were only 8 party slots available (later increased to 16).

It was the other way. 1.0 started with 15 players max. in a party and it got reduced to 8 players some months later.