How possible would it be to flag NPCs as party members?

[Replacement]

We have a fair number of missions that have some pretty cool NPCs hanging around and helping out.  We have tech for powers that summon pets.  I'm curious how big the technological hurdle would be to have them show up in our Party list (and thus count against the limit) instead of as pets (or not at all, or mission allies).  A lot of older MMOs have systems like this, to help sustain lower populations.

 

And of course, curious how others feel about this: a way to build a limited party by yourself.  Cheap, easily-summoned allies that aren't so abusable because they count towards those party limits. 

 

For implementation: Ideally you would add some additional criteria like "only 3 total NPC allies to a party" and/or "no Allies in leagues."  It'd also be cool if there were criteria to unlock them that roughly matches progression.  Example unlocks:

• Back Alley Brawler by talking to him in Atlas Park and then he gives you a short mission to click on plaques or collect some badges in King's Row.  Gets folks an early bruiser that would help out controllers and defenders, particularly.
• Finish both Positron arcs to unlock him.
• Run the tip mission with a converted Frostfire to gain him as an ally.
• Some of the bigger names could come with longer cooldowns so they don't seem to be popping up in every solo crew.

 

Thoughts?