Its been so long since grouping was fun for me in MMOs, I just don't play MMos anymore. If i wanted to play alone, i would play solo RPGs like i do (currently playing wasteland2 which is fantastic). I have no hope left that we will see a real group based game again... its all about the solo experience but I for one will never get it.
I tend to play alone. My play times just do not work well with others. And when I do play, being forced to play with idiots can be annoying. everyone in your party might have a different agenda. you want a leisurely dungeon crawl, they want to farm gold, skip bosses they don't care about, etc.
the main issue I see, is not even that all these games focus on making MMO's solo, which you are not wrong about. but worse, they go about it in totally the wrong way.
gw2 did some decent work with its DE events and automatically sharing of exp. everyone is essentially automatically partied. joining up to do things happens super casually in that. like my story in the gw2 thread about the people that helped me with the jumping puzzle last week. the game naturally encourages everyone to join together.
But the real issue I wanted to point out, is the difference between playing together and community.
Like, being forced to play WITH someone literally in a 5man, 10man, etc is playing together. And is that really what everyone needs?
You say you can get solo play in solo rpgs. But again, the community aspect is the core. and the thing really few games have nailed recently.
Like, I as a solo player have little to no influence on the community, game world, etc. THAT is the problem many games fail at.
Way back when in UO. I could mine, and sell my iron, etc to guilds, high end crafters, who all needed it far then even my solo blacksmith/miner did. In most games now the closet you come to interaction is just the AH. and even that is just the UI essentially..
Gw2 almost had something like that, with the Jumping puzzles chests and "donating" to the guild that did the mesmer portals for you. As a solo player, the fuck do I need an omega golem pattern for? THAT kind of shit, should be the norm. gw2 has guild banners, which again, lets guilds give buffs to everyone... but what value does "everyone" have for the guild? Imagine every jumping puzzle in gw2 gave seige weapon patterns. Tuco, would PRX have not been running them, and escorting new players, etc through them as well? which is where pvp games fuck up.
Solo players should be a commodity for guilds, etc. Maybe the fealty system here will be this. As a solo player, I should provide something valuable to guilds, so that even if I am not in their guild, they actively want to protect me, and benefit from my existence. And other guilds may potentially try to recruit me away from their protection.
I as a solo player should harvest/generate/collect far more materials then I can use in solo play. some maybe even outright have no use for at all. While guilds should have a need for those materials in excess of what they can personally harvest/generate/collect. And it needs to be key that these are exchanged via trade, and not hunting the solo players.
I should note, GW2 while encouraging everyone to join in its pve, does fail at one of the opposite aspects for the same reason.
As, I've also said, fighting over resources is by FAR the best pvp experience in WoW. Fighting over thorium, herb nodes, etc. gw2 kills that totally by having all nodes unique to you. even the ones in WvW.