I don't think so.
Ran'jit is exposited as being untouchable by your same allies that later go on to battle an original Ascian. It's silly precisely because what's being exposited is drastically different from what's being shown in gameplay. He also doesn't consistently use his same moves. He never uses the Mega Raiton again after the first encounter. He only seems more integrated with the plot because he has many interactions with your NPC allies. His role could basically be filled in by any bad guy the writers wanted to use, but it's easier to reuse the same guy over and over.
I don't know why you say Zenos had no stake in the plot. Zenos drove the entire plot of 4.0. The attack on Rhalgr's Reach was his response to us destroying that prototype and killing its associated squad. He's the commander for both fronts, but leaves Doma in Yotsuyu's hands, because the imperials found Shinryu bound by Omega. He let the Doman Liberation Front grow by deciding not to kill those villagers. He had Fordola imbued with the Resonance. Just because they're not on your butt 24/7 doesn't mean a villain doesn't have stake in the plot. It just means they're a power bottom. /wink