I think that would be a more interesting way to have mercenaries in the game.
I dont see any difference.
You just stated that glass is half full, instead of half empty.
If you don't see a difference, I'm confused. There is a difference, which must mean I didn't explain what I was saying properly.
Building a custom party is choosing a group of custom characters.
The version of mercenaries I'm talking about aren't custom. They are prebuilt NPCs in the game that can be hired at specific locations. They would be named NPCs with prebuilt stats and classes. There wouldn't be an endless number of them. I'm not talking about full blown personalities though. Just a couple of lines of dialogue each, and maybe a small backstory.
Whereas in a custom party, you could pull in endless choices in as diverse a manner as you desire.