Personally, I'd prefer that they just give preference when assigning roulettes to players that have the new status - for post-50 dungeons or pre-50. It solves some of the pain on a new class' release for anyone who's still new to the game, it helps them get into and learn content faster, and does basically the same general effect.

Deliberately adding a separate roulette for new players, as nice as it sounds, will be ignored by a lot of players deliberately because "I don't wanna teach some noob" and/or result in more trolling than we've already got.