I think it’s time to have Merc AAs be autogranted like player AAs, and earned regardless of mercenary being active by utilizing a toggle on/off like the old leadership AAs. The Merc AA experience rate is too slow and creates a similar problem the leadership AAs created where only 1 player benefits from the efforts of the group. Also, if you actually have a full group you do nothing to progress your mercenary for the times, when you don’t have a group or need your mercenary to fill a role in the future. All in all this would be good a change to maintain the health of the game for everyone from existing players to returning players and new players. Realistically an auto grant would be the least time consuming of my suggestions.
My assumption is they are wanting to be able to assign points spent on one type of merc to another. Say at one point you had all of your healer merc AA's maxed and then a couple of expansions go by and now you are behind on your healer merc but you had assigned points to your tank merc but never use your tank. Just an assumption and personally I think this would be a good idea if it came with a penalty so people cant just reassign points every time they bring out a new merc type. Maybe a 2:1 conversion to keep people from abusing it.