Fenes said:
If someone takes a leadership feat, then we handle it by letting the player create the cohort, and by considering the cohort as loyal (to the death and such, unless specified otherwise). That's quite a difference from the rest of the "followers".
True, but the problem with that cohort still remains. I'll take one of worst case scenarios, you have a druid with leadership and a young druid acolyte (your cohort). So now you have 2 druids and 2 animal companions to dictate moves to each round. Further, the animals often have multiple attacks. So now you are figuring out spells to cast while rolling lots of attack rolls, and calculating all the damage. This can take a large amount of time, far more than other players.
Now in 4e, actions do seem quicker, so that would help somewhat. But there's still an underlying problem that with your feat not only have you acquired more power, but you have acquired more spotlight time.
The design question becomes, can we:
1) Provide a companion that has an insignificant amount of time dedicated to running its actions, so it does not greatly affect the economy of actions.
2) Provide a companion that provides a reasonable benefit, one that makes the companion worthwhile.
3) Within the system make the companions limitations believable enough, as supposed to just some mechanical handwave.
As this thread has indicated, from a design perspective this is VERY HARD thing to do.