If i’m honest, i’ve never been happy with coated cables, we’ve often found them to feel draggy, and sometimes find the coating seperates and clogs the outer. If we build a bike that’s a nightmare to replace cables on(step forward Trek Madone), we’ll replace the enners with slick stainless before we start. Another thing to consider, you haven’t mentioned whether you’ve changed the outers, if you haven’t, then most of the time you’ll be pi**ing into the wind, as that’s often a big part of the problem you’re trying to fix. Shimano SP41 outers with sealed SP4 end caps, and a slick 1.1mm stainless inner from the likes of YPK or Elvedes (though others may work as well) are all we’ll ever use in our workshop.