Ranking Up - Guildleve changes

After reading through the Letter from the Producer XII, I felt quite relieved that Guildleves are to be aligned to solo play.

What I am confused about is what the primary means for ranking up will be? If you are a casual player this is fine but what if you play for long periods of time? Behest cannot be the primary way to rank up, does this mean that world grinding will be focus for groups?

I would be interested to know what Yoshi P has in store for us to get to rank 50 with group oriented play.

party-based exp. dunno if old grinding camp or dungeons

I hope they figure it out very soon if 1.18 is going to overhaul Guildleves!