Interesting idea...but HVS has already confirmed no allies except NPCs you can talk to. It would be nice to see Sorbo (if he's Prometheus in the next one) actually go Herc on some people in a Scarab body, smashing the lower drones into walls and stuff. Better yet...give him an Invader body : P. As for Ford getting a lady friend, it would complete the Secret Agent Gone Rogue archetype he upholds...though she might only appear in cut scenes, as if she were known about, Adams would have her targeted. All that said, interesting concept.
No allies as in no AI gun toting character that fought alongside you. Like Sgt. Johnson in Halo or someone else from another game. Prometheus has been just a guiding voice with no physical interaction in the world other than events flowing around you. Now he's in the ASE, so he's actually a "useful" character. He is your ally in that he aids you through advice. It would be nice to see AI allies to give you fire support, but I don't think HVS is going to do that.
But in this your ally would be Prometheus...hopefully voiced by Sorbo, thus giving his scarab godly powers of Hercules and allowing him to eat your friendly fire bullets like Doritos, and then maybe pop an orange soda afterwords. But yes I agree, they do tend to get in the way.