Blizzard's Micah Whipple, best known by the name "Bashiok" on the official Diablo III forums, has answered numerous questions posed by the community on the subject of follower mechanics.

Whipple revealed that Diablo III's newly announced NPC followers will not be available outside of the single player experience, as their addition to a packed multiplayer game would make the game too hectic for players.

Well, followers are essentially a flavor bonus to those playing through normal the first time by themselves. It provides some story elements, but more importantly it gets the idea in their head of playing with another person. You come across each of them pretty quickly in Act 1, and then they help you throughout the rest of the game if you'd like. They aren't required to beat the game on Normal, even if you're playing by yourself. Feel free to leave them behind if you like. But they are pretty awesome. They're also tuned so that they become very weak starting in Nightmare, and then are completely unusable in Hell. Even if you're playing alone, you will probably not be using Followers past Normal – – you can try but they're going to just be one-shot back to back. They're there as a bit of flavor, to help get people into the mindset of co-op if they're a bit reluctant, and… that's about it. They won't be usable at end-game, and they'll never replace the abilities and power that another player can bring. … Followers are for solo-players in Normal and maybe into Nightmare. That's it. If you have a friend to play with you won't even be able to bring them with you. … Normal is not hard. You don't need a follower. I think they're cool and why not bring them along. They're essentially wandering DoTs most of the time (that talk). From a mechanic perspective I don't know why any level headed person would refuse to take them. (maybe though that's why this is an issue for you… 😉 On the note of eating crow, a lot of people yesterday were really upset that followers were going to be required for the entire game (somehow based off a video of Act 1 Normal it was able to be discerned how the entire game would be balanced). Then there were quite a few people defending it and trying to make sense of a video without any context. Both people were wrong in their arguments, thus, that's why I said that.

Upon revealing this, Whipple courted complaints from vocal community members that followers were a "waste of development time."

I don't mean any offense, but you don't represent the majority of people that will play the game. For better or worse. People here, logging in with their Diablo II keys to talk about an unreleased product – – on an essentially hidden forum – – do not represent the vast majority of people that will play the game. Which doesn't mean we don't want the game to appeal to you or be a lasting game you'll want to play as long as you played Diablo II, it very much is our intent to be, but we have a broad range of Diablo fans to appeal to. Looking at Diablo II the amount of people that bought the game, never logged on to Battle.net, and never went beyond Normal are not insignificant. In fact, they're a substantial portion of the people that bought copies throughout the life of the game. The same goes for StarCraft II. Many (maybe most) people play through the story on normal difficulty, they MAY jump into multiplayer for a bit, and then that's about it. Putting effort into ensuring their experience is a solid one is not a waste of time because some other people completely skip the story and go straight to the 1v1 ladder. Followers fit in with that 'average' use of games very well, but their intent is to also help people expand beyond their initial intent of beating it on Normal, and then shelving the game. If the followers can get a player excited about co-op because they like playing with another character, that's a win. We also think they just add a lot to the experience up front, which is important. And, they're memorable characters. I don't think the scope of who these people are needs to end because their health doesn't scale so we can ensure the end-game is pure and there's less visual noise in multiplayer games. We don't have any plans for them beyond what we've announced, but, I wouldn't be surprised if they became meaningful in other ways in the future. Even if they're not, if someone enjoyed playing along with them, enjoyed the dialog, and liked what they add to the single player experience (which is pretty significant) then that's not a waste of time. … Normal is super easy. It's intentionally super easy. You will die, but you can essentially slap on gear and not think too much about it, and probably beat the game without too much trouble. There will be many people though that will get a good amount of damage and utility by keeping their follower along. But, realistically people aren't going to actively refuse the help of a follower as they play through the game the first time. I can beat the game on normal without gemming any items. That doesn't mean gems are a waste of time as a system. One happens to be required more at higher difficulties, one happens to be more useful and fun when playing alone in Normal. There's nothing that says all of our mechanics have to be useful at all times through all difficulties and classes or else it's a waste of time, and in fact, that'd probably make things super boring. … Followers were originally going to be available during co-op, and actually are right now because of a bug in the current build we're playing. And it's crazy. If you're unfortunate enough to also have a witch doctor, it's insanity. Eight characters running around plus all of the potential pets. It's complete chaos. That's the biggest reason they aren't going to be available outside of single player. We also love that they're these strong, vocal, named characters that have a place and point in the world. They have objectives, they have opinions, and when you're by yourself it's awesome. They'll chime in and offer a comment on something, and it just does that much more to bring the world to life. But, in a co-op game, we all pick the Templar, and all of a sudden there's this character in the world cloned four times, with the same voice, saying the same things… and it gets real weird real fast. Also they do tend to talk a bit, and having four followers all piping in at different times can be pretty annoying when you're trying to talk with your friends. There is actually the situation where you can have a follower and then re-run the quest where you pick them up, which could be a little weird, but we have some creative solutions we think keep that specific paradox from unraveling the spacetime continuum. Followers have been a feature and we've known who these characters were going to be since before we announced the game, and while they haven't been in active testing that entire time, we're pretty well informed in how we feel they'll play out best. Of course, iteration is the name of the game. I don't really see the current plan changing, personally, but I'd be willing to be wrong. I just don't see a potential for (clean) alternative options outweighing the pretty massive negatives that these rules correct.

Whipple discussed the company's reasoning for keeping followers in the single-player experience.