Adrenal Speed is meant to increase a character's overall speed, allowing them to perform more actions per round.
One thing to remember though is that the original version of the skill was designed for use with the original initiative/tactical system. Even when that system changed for RMSS/FRP, the skill still remained the same.
In RMC, the skill still remains the same, but that is because ICE did not decide to change the tactical/initiative system until after Character Law had been released.
Personally, I think that the simplest method to handle it would be, IF the maneuver roll is successful, then the character gains x% activity, where x = total maneuver roll - 100. Thus, if a 175 is the total for the maneuver, then the character gains +75% activity to use for the round.
The problem with requiring it to be learned for each weapon group is that you are then tying the maneuver specifically, directly, and only to attacks, and not other potential actions.
Now, putting limitations on the skill such as no heavy armor, that I could see quite easily, as the armor slows you down.