Roulettes assign a random duty based on available duties and parties searching, IIRC. Many people in this thread are proposing people be forced to do a duty based on their highest possible ilevel or character level which, yes, is forcing people to play a specific way. I sure don't want to do the nier raids every day, that sounds as boring as doing crystal tower every day. Crystal tower, even assuming people aren't manipulating their gear, gets more play than the others because it's the only alliance raid that's mandatory for the story so it's the only alliance raid everyone in the game has unlocked. It's also the lowest item level so everyone from ilevel 50(90?) to whatever's current is applicable for it. Statistically speaking, you're going to get CT far, far, more than anything else. But on top of that; it's fast, it's easy, it has rewards tied to shadowbringers' relic weapon, and its time to exp ratio is far better than any other alliance roulette. If I'm doing the alliance roulette while grinding my weekly tomestones I'm glad to get CT because that means it's going to be a fast run because I'll be honest: none of the alliance raids are particularly exciting after running them a dozen times, some less so than others. The fact that the other ones are longer and comparatively less rewarding just makes it suck to get them. Like getting Castrum instead of Praetorium for the daily MSQ roulette. But I don't see people throwing a fit and demanding we force people to march through the slog of castrum.
If you want to do other alliance raids so bad, then queue for them. Trying to change the rules on how the alliance roulette works is only going to kill the alliance roulette as there's nothing to really compel people to even unlock the other alliance raids, leading to hilariously longer queue times as it stratifies people between the 50/60/70/80 tiers.