good thread, some nice ideas floating around in here. I definitely agree with a lot of the themes of having content where it is highly randomized and enemies hunt you kind of deals

World Grinding should always be an option, but it shouldn't be so focused on that people feel they have to do it to progress. I kind of feel world grinding as it is now should be for short term solo content. If I have a half hour to burn and am hungry for a fight, I can go rage on some sheep for a bit, leave with some SPs and maybe a few items I was looking for, then get on with my day.

If I get some strong balanced party together, I do not want to fight that same sheep just ten ranks higher, I would prefer we spend our time and use our talents for something more interesting. Clearing Dungeons could be repeatable quests that reset once in a while and give bonus sp as a reward. Or systems like Assault/Nyzule, but with SP rewards tacked on to the end of it to reward your effort. Just something so that you are working towards a clear goal, and SP it tacked onto it, not working towards a clear goal of getting SP. "1.5k tnl guys! oh the PLD has to go to work ohh.."

But my real suggestion for group party sp dynamics;

Random Battles! Roaming the terrain near enemy encampment is risky business. Entering these areas with a large group might seem only mildly threatening, but you will soon find that you are the ones being truly hunted. Depending on monster influence in the area, as you are grinding on the local scrag your group will randomly be thrown into instances where any number of the corresponding beast-men will try to take you down. Their numbers and strength, though somewhat randomized, will be dependent on how large of a threat they see you as. A full party of strong adventurers could find themselves pitted against some very unique and powerful fiends! Of course this wont be offered much to solo adventurers, since the enemies will hardly see them as a real threat (but small 2-3 enemy random battles could be fun for soloers). You would be granted some nice SP per each encounter you survive. As for monster influence, it could be something set in stone in the geography of the land, or even something ever changing and updating, like Xi's conquest system. If tons of people are falling in the area, the enemies and random battles will get much stronger, but the rewards would be worth it! to motivate people to get out there and try to reclaim some bit of territory (this idea could also tie into companies but I am getting too deep into it and rambling )

of course, screen crashing would be optional, as well as victory dance