Re: Games and all things related
The way I see it, unless it's seriously ruined the actual story line, or they've had to spend less time on it than they could have or there are parts that are co-op only. I don't see how a co-op function would be bad for it. You have 2 people as back up anyway, why not have the option to have a friend or two of yours be able to control them and play alongside with you.
I would be a lot more interested in both Mass Effect and Dragon Age if they offered a co-op option for the main story line.