MadMonkey while its true that mmos are conceptualized with party play in mind, its very difficult to put it in actual gameplay when the server only has a handful of players online at a time it could be very difficult for new players to insert themselves into established groups, which can lead to feeling of being alienated.
If you give a gamer a significantly more efficient way of doing things, they will always feel forced to take that route. Example of this is geffenia before nerf, it was the most efficient zeny farming method on the server, it is not mandatory to do it, and yet people complained they are being forced to do it because its most efficient.
Same thing with party play. I never did say it should be equal to a solo player, but it shouldnt be significant as to make people feel they are losing out A LOT if they choose not to partake in that activity. Its okay for it to have better rewards, or even exclusive rewards, but never to the point of making solo players fall far behind. Emphasis on the A LOT, while I do agree group contents should yield better rewards than solo, the gap shouldnt be huge as it will make people feel forced.
A server with 150+ players online is just not big enough for a game to centralized everything in mandatory group content, and while the group content isnt technically mandatory, if it offers significantly better rewards than not doing it, people will still feel forced to do it.
And maybe this is just me, but for me, private servers like this are usually more of a pick up and play game than a game that requires full dedication. Its more of like diablo4 , while eternally only and you can socialize, its fun gameplay lies on the mindless farm looking for that uber unique drop (mvp card) than an actuall mmo like WoW or FF14.
But all this is just an opinion of a person with social anxiety, if it will actually help boost the server's popularity and success, then i wish muh and ice all the best! Ive been to a lot of servers and this by far has the best community, and i think it deserves more success.