I believe the 4th suggestion is basically a dual spec like WoW has, although a lot of people believe that this type of feature can ruin a game, because it will allow one person to fill multiple roles, but like every game that implements this type of system, just because you have the second spec does not mean you have the gear to fill that roll., Also there needs to be some restrictions met prior to being able to learn something like this, such as I believe you should have to be max level, as well as it should cost enough that it's not something that you buy just because you can. It should also not be something that is required just to be able to play. I hope that's sort of what the OP was referring too.