Gillen has talked about this a bit in interviews, but I actually think there's a pretty big difference between Gillen-Uncanny Sinister and Krakoan Sinister (including Gillen-written Krakoan Sinister) if you go back and read. The Krakoa-era take on Sinister (Hickman & Wells, mostly) took what Gillen did on Uncanny and really focused on some aspects of that over others, playing up the campiness and the humor as well as some of the unique weird things Gillen had Sinister do with cloning (though Gillen goes harder on it). Gillen's Uncanny Sinister is a little bit more sadistic and feels super victorian-inspired to a level current Sinister doesn't. Gillen describes it interviews as people really taking what they felt worked from his take and molding that into their take. And of course when Gillen came back to Krakoa, he's now trying to write Sinister that's in line with the take Wells and Hickman had.