I was inspired by that Eornheit image in the opening post... but didn't like the head. Then thought "who needs a head other than Vay Hek?" No one. Because we're possessing the damn things.
The Grineer attempted to retrofit this sentient fighter drone for their own use. Unfortunately the only thing they managed to achieve by using infested tissue to "quiet the sentient bits" was making it compatible with transference.
This hovering amalgamation of grineer and sentient tech looks more like a Gerwalk Xiphos-lander than any people frame. With stubby thruster legs and spindly guns instead of arms, the frame must use energy fields to 'poltergeist' other weapons around itself (they're just glowy beam effects instead of solid warframe-looking arms is all). It focuses on qualities normally found in annoying enemies and things we normally have to smash up: quickly moving around in 3d, and having more than one gunport firing at the same time.
The idea here is A) making use of the fact that hovering frames like Wisp are now something that can be done, and B) exploring not-people warframes because hey, that's a look the other frames all lack.
This would give us a sentient with Grineer thrusters strapped to it (to compensate for the armor they added over those spindly joints when they Clem'd it) ready to have its refined alien finesse smashed around in a good scrap. And like any good Sentient, it can also make some calls.
Abilities could include flight or a weaker form of resistance gating (with limited duration)
One ability of course would switch to the integrated quad beam guns: fire modes medium-ranged (long for beams, maybe 100m or so) sustained burners that run parallel for good coverage but have difficulty hitting smaller targets with all four all the time, or a charged up missile swarm from everywhere (more ports on the frame as ability levels up). Because you deserve anti-ship railjack turrets in small and cramped corridors: you're worth it.
For another, where ramming your Oxium Osprey is a suicide thing, ospreys have neither the toughness of grineer armor nor sentient adaptation to make this tactic viable, but you do. Don't kill yourself by ramming; turn all that potential into energy. why break when you crash when you can electrocute things and regain energy like comets do? Of course comets do that; the Grineer wouldn't believe it if it weren't true.