The only roulette I find to have excessive amounts of lower leveled content is alliance raid roulette. And that is due to three reasons:

1. People only need to unlock the CT raids to have access to it;
2. People refuse to unlock the others thinking they are hard(they aren't, people just need to pay attention rather than "Netflix and XIV");
3. People ilvl cheese because the rewards are so unbalanced the whole roulette needs a major overhaul so that the higher the leveled content, the more rewards you get(gives more incentive to actually queue fully equipped, and unlock those other raids that require paying more attention).