If they add coil into a roulette, it will be like pre-nerf steps of faith in trials roulette all over again. People will start avoiding that roulette like plague in fear of wiping and end in failure. Unless SE decides to reward those who do the raid roulette say at least 300 centurio seals for T5, T9 and T13 to make it worth it (heck even if so, I doubt many people would bother when hunts are around). The problem with coil is there are so many one shot mechanics, if you have half a group of players who have absolutely no clue as to what they are doing, and/or if they don't learn quick enough (Which is usually the case, not many quick learners out there), the duty is doomed to fail.

With that said, I agree with CT being in a roulette, cause I don't see why not, I never seen a failed CT run. I saw a few hiccups, but nothing too bad except a couple rage quitters maybe.