Given that traditional groups are optional for all other content in GW2, it doesn’t seem to fit that dungeons require a full human group. If the design goal with this game is to let people play how they want to and be relatively “solo-able,” there should at least be some option for solo players and small groups to enjoy this otherwise isolated content. Adding “henchmen” seemed like the most logical choice since the AI (however imperfect) is technically in place already, the characters already exist, and the mechanics of an NPC party is already known in the Guild Wars universe. I don’t think this will deter people from playing in groups (especially if the reward percentages are scaled down with party size), but will instead make people more comfortable joining random PUGs once they’ve gotten their exploration and cutscene fixes out of the way and feel confident in their ability to run that dungeon effectively.
The closest in-game analogy outside of dungeons is personal story missions where you’re already escorting one or several NPCs. It really isn’t that far of a stretch to imagine these types of AI-controlled allies being available in dungeons as well, fighting alongside you like a normal party. In fact, the NPC friends you make along the way in your personal story (eg. Demmi Beetlestone, Almorra Soulkeeper, etc.) could even be the henchmen, further integrating dungeon play with your personal story. Completing certain story events could even effectively “unlock” these types of additional allies for dungeon use. Lots of potential!
I actually really like this idea. As it is right now I don’t find myself caring a lot about the NPCs you meet in your personal story missions- some of them stand out more than others but the personal story progresses very quickly and many of the characters present in it do not appear for extended periods of time. I would be much more invested in the characters if they were people I could unlock who would then assist me in dungeons or similar situations- this worked really well in GW1, where your heroes were not only random npcs but also some of the main characters you encountered in the world. Not only that, but it was fun to unlock extra heroes that were only available outside of the primary missions- I would definitely run around and try to unlock as many hero/hench npcs as possible if they were available in GW2, even though they would only be available for dungeons.
And I think it is also true that honestly, GW2 doesn’t really encourage traditional group play right now. Even though you are constantly around other people and do interact with them you aren’t always in a group, and you really don’t need to be outside of instanced areas. GW2 has a good balance of encouraging community interaction while making sure people who prefer to play solo can still do that and not be at a disadvantage. It would be nice to see them carry this forward into dungeons.