I think the matched parties working all the way up only comes with benefits comparatively to the current system where there is also a floor series that gets spammed for leveling. Perhaps the problem is that there is no extra xp rewards and incentives to actually do a full run? Imagine if going for the full run was able to give like +50% of xp per hour spent comparatively to spamming a series (arbitrary number)? People could still choose, but you bet people would tend to go for the full run, thus making all floors pop in theory.