A few days ago, I was reading about Tesh's frustration with Heroes and henchmen in Guild Wars. (The article is actually about quite a lot more than that, and a good read, but venting about henchmen was a part of it.) I happen to share that frustration. Though the flag system in Guild Wars offers some limited control over henchmen, they aren't as sophisticated as I wish they were.
Collecting Heroes is a great feature in Guild Wars. I think more MMORPGs should make that a standard part of the gameplay. Instead of having the world split up between soloable "normal" mobs and heroic "group" mobs, which is simply weird, have all monsters be group mobs, and allow solo players to collect AI controlled NPC party members for the occasions they can't find (or don't want to find) other people to play with.
I'd like to see an MMO take give us the ability to collect henchmen/minion/Heroes and then take it a step beyond that: give us the ability to train them over time. Like any good RPG, this should be something we have to work at! The minions might start off requiring a good deal of micro-management but as we work with them, eventually we would earn the ability to get more flexible allies over time.
One RPG that I thought had a really clever NPC control mechanism was Final Fantasy XII. The way it worked is each character in the game had a certain number of "gambit slots". Each slot could take a simple order, which amounted to a command that executed under a certain condition. The orders were prioritized with the highest priority commands declared first. The command with a matching condition with the highest priority would execute.
From 1up, an example gambit setup.
For example, a simple healer might have two gambit slots:
1) IF Players health < 50%, cast HEAL
While my player's health remained at or above 50%, the healer would attack our enemies. If it went under 50%, the healer would cast heal unless they ran out of mana (the condition would already fail if they couldn't cast). At any point, I could also order that the entire party follow me and flee.
Characters started off with very few gambit slots; these had to be unlocked over time. Towards the end of the game, most of my characters had seven or eight gambits, dictating how they behave in specific circumstances. During the game, we would have to buy or discover new gambits to gain more fine tuned control of our allies.
I'd enjoy seeing something similar in an MMORPG. In addition to collecting new Heroes, leveling and gearing them up for battle, we would also have to improve our "leadership" abilities by undertaking difficult missions; the rewards from these missions would enable us to grant new gambit slots to our allies and unlock new gambits to program them with. It could also introduce more depth to the system than the Final Fantasy version had, perhaps by introducing gambits related to camping and pulling. I'd even enjoy PVP minion battles between henchmen where gambit selection is the major determinant of who wins or loses.
A system like this would add some additional depth to a henchman system and provide some lateral forms of character advancement. It also makes existing itemization more valuable since it doesn't sting as much to fight your way to the bottom of an epic dungeon only to get NO-TRADE drops for a class that isn't even in the party when you have a henchment that can use it. With Heroes that you can equip and train, everyone has a potential use for every drop. (Though I guess that could complicate Need vs Greed.)