So the premise would be to re-build SHIELD with name characters. Not a bad idea.
I could almost see Cybertek helping SHIELD, now that the "incentives" program is presumably gone. They'd just be working for $$ now, good or bad.
But I don't see Quinn working with SHIELD. He's too self-interested. He's got the Gravitonium (right?), and once Dr. Hall emerges, i think that Quinn will either manipulate him or (more likely) be Graviton's first casualty.
Well! not only known agents, I love to get attached to brand new character, but they have to be well crafted. Another 10 episodes with the presentation of new characters could be annoyng, is the reason why most of the people leave the show.
I think that this known character could be nice recurring casts, the team have to be brand new, why not with interchangeable characters depending on the mission.