Tbh, whilst I'd love to see a co-op mode, I'd rather the dev time was spent on building a truely outstanding single player experience. I don't mean to sound antisocial, but there have been a lot of games released over the years with an almost mandatory co-op/multi mode bolted on where it doesn't really add much, is rarely used, and often detracts from the single player experience because once you start incorporating multiplay into the experience, everything needs tweaking, not just monsters and equipment, but also even the layout of maps to prevent abuse, and normally this process only servers to water down and diminish the overal experience.