Sadly, there is absolutely no reason for coop as of now. Besides the servers straining under the load...
- You can't "farm" items. PVE enemies scarcely if ever drop some of their clothing items, all of which are ragged and dirty.
- Moves are best farmed solo, as an open session more often than not results in someone killing your opponent (and some moves can only be learned form what amounts to "rare spawns"), or some friendly fellow player deciding to gank you, since you're most likely already half-dead, anyways. Which nixes the progress. Not to mentions some of the moves are performed only ever s0 rarely by the NPC that have actually them in the first place that farming them is a drawn-out, sordid affair...
- The marked ones don't seem to drop anything, or if they do, their drop rates are abysmal. Killing the same guy 40 times over with nothing to show for besides the moves isn't fun.
- the Boss fights can only be done solo, with the "farmable" versions locked behind PVP progress. A scant 100-300 matches with 3 rounds each, depending on your skill. And they have to be combat trials, which put you against random strangers, anyways.
- new weapons can only be obtained through combat trial levelups. Sadly, they indeed have different stats, and since the rewards gained are totally random and include stuff like duplicates of the starter gear, you might as well never see another one. Oopsie.
TL;DR : You don't need friends here. At a certain point, you probably also don't want any, as they're counterproductive.
Maybe some patches and new game modes will change that, but as of now, it can be neatly summed up with "don't bother"
Post edited September 03, 2017 by vonHardenberg