I've been scrounging through Dragon's Dogma info for a while and whenever I look at forum or youtube comments, people always seems to complain that the game doesn't have multiplayer.
I don't blame people for coming to that conclusion. If you look at the game from a far, it looks quite similar to something like Monster Hunter, which is incredibly popular because of its multiplayer.
However, if you study the Pawn system and some of the problems that can occur from information overload, I think it'll become evident why it shouldn't have co-op and why it's a lot closer to Final Fantasy something like Skyrim.
As you might know, a Pawn is a NPC companion that you create in the game to support you during your quests and gains levels along with your character. As other players use your Pawn online and as you use theirs, the pawn doesn't get XP, but they do have a rating on the different monstertypes and quests in the game. When they come back they will then be able to help you with tips on where to go next and how to combat monsters.
Now, another player could do that too, but I actually think that it would ruin the sense of exploration and adventure that you get in the game world.
For instance, if I played a public co-op game where Naruto420 joined my world, he might tell me "Oh, if you go up here you have to fight the skeletons with fire magic, so you can get the Goblin Blade and 5000 gold". Sure, it's helpful information that another player can help you by telling you where to go and what to do, but in my opinion it actually breaks the immersion of the game and the personal joy of discovery.
It's the same problem Journey has. When another player joins my game, we can't communicate, but if they know the solutions to all the puzzles, they can just run through it, effectively lessening my experience with the game.
Of course, this is example is all assuming that the random player you meet is friendly. There are tons of things a malicious player could do to ruin the game for you if they wanted, including the ability to physically pick up other characters and throw them off cliffs, run away from the group and not help you in combat or even stealing loot.
Certainly, they could change the game to balance all that out, but then I think it would be way too similar to other games.
Dragon's Dogma "passive" online functionality is what helps set it apart and that is one of the major reasons I'm looking forward to play the game.