One of the big questions, as well as debates, has been whether or not mercenaries should or could be part of Diablo 3. It’s been indicated that there will be two sorts of mobs that will assist players; hirelings and mercenaries. Hirelings appear to be a type of NPC that can can be enlisted to help a character for a short period, or while on a particular quest. Mercenaries function much in the same way as they did in Diablo 2, meaning they will be purchased via gold and will have the ability to be geared up.
What’s not known is whether or not Blizzard has plans to implement any other features into the follower mechanic of mercenaries. For example, will we have more control over them in Diablo 3? Being able to control the aggressiveness of our mercenaries would be a definite plus, as well as having the ability to send them on specific targets.
Another feature that would be a welcome addition is enabling mercenaries to function like porters as well, similar to the pet’s role in Torchlight. The additional inventory space, along with the added convenience of being able to send the mercenary into town to vendor loot, would be a huge bonus to game play.
Some players are indifferent and even opposed to the idea of mercs in Diablo 3, because they view them as relatively useless gold sinks. In Diablo 2, this was true to an extent, however, giving players more control and customization over their followers would make them much more useful and less of a liability.
It’s not entirely known what sort of tag-alongs our heroes will have access to in Diablo 3, but it’s pretty certain that the mercenary will return in some way, shape or form.
This is all Bashiok had to say on the matter, indicating that the Blizz devs are nowhere near settling upon a final system for mercenaries.
Quote from Bashiok
We’re essentially on the same design threads we have been since before announcement. (Source)
However, it’s pretty safe to say that there will be something unveiled at BlizzCon 2010. In addition to the announcement of the fifth and final character, I expect mercenaries to be another big feature of the Diablo 3 buzz at BlizzCon.