If I'm not mistaken, depth mobs had lower stats than intended before, so this is just a bug fix really. It's a shame that it wasn't noticed until now, but it can't be helped, reverting this change wouldn't make any sense. If players in official server can farm there, then I don't see why we wouldn't be able to.
No parties are formed, most of the server's veterans already got everything they needed from that dungeon.
Depth parties are weird in the sense that there are always players who want depth parties, but no one wants to create their own party, either because it takes time to recruit enough people, or because they don't know enough about depth and don't have the confidence.
That's why, when a new player that is willing to recruit for depth parties shows up, you see a party in depth every day. Then it stops when that person gets enough reputation. That's why, if you look at #lfg logs, it's like a cycle of 2 weeks of depth parties and then about 2 weeks of no parties.
What I want to say is that depth parties can happen, I myself collected reputation purely through depth parties, and it was just recently, I reached 1500 reputation just last week there, never farming solo. It took a few weeks. Honestly you just need to either recruit parties youself, or wait for someone that is willing to do it.
Also you still have the option to buy depth samples as an alternate method of getting reputation. It's 16 reputation per day per character, so assuming you have a few characters that can take the quest, it'd give reputation at a pretty decent pace. Although it's kinda overpriced at the market rn.