I think that the constant CT is mostly not a result of people unequipping their gear. Even if you are required to wear level-appropriate gear to sign up for the roulette, I still think you'd see Crystal Tower most of the time because there are simply far more people who qualify for it. It's the lowest level alliance raid, and the only one in the MSQ. So if you get matched with even 1 person who is below level 60 or who has not done any side content then you will get CT, guaranteed.

I think if they were to force you to qualify for more raids to sign up, you'd see more people dropping out of the longer/harder raids if they didn't get CT, and it'd make alliance raid harder to join in general because of the stricter requirements.

IMO the solution should be to separate Crystal Tower into its own roulette. People who only want easymode CT get easymode CT, and everyone else who is cool with anything can get a bonus non-CT raid to do each day. Right now even if 23/24 people in a roulette were fine with any raid, if even one person insisted on CT then everyone's roulette bonus for the day is used up on CT and so they can't populate anything else. Separate roulette solves the problem completely.