I don't think it needs any changes. I always thought the EXP/GIL/Tome reward for doing leveling duty roulette (and trial/guildhest roulette as well) was because you had to queue alone into a dungeon not of your choice with 3 other random people, with some (most in my experience) of those people possibly being new to said dungeon.

Of course it would be more convenient for everyone who has played the game for a while and has friends/FC members to get a group of 4 and absolutely destroy leveling roulette for a quick and massive boost of exp, like what most of us do for Expert for Esoterics now. But that was not, in my opinion, the main purpose of implementing leveling roulette there in the first place.

Aside from the Leveling/Main-Story/Guildhest/Trial/PvP roulettes and certain story-based or class-based duties, this game doesn't actually force you into solo queue-ing much, and you'll eventually spend more time with your friends/fc/static doing EX primals, PvP, dungeon-leveling, fate-grinding, Alex N/S, Expert and Hard Mode Roulettes and other older raids like Coil.

I don't see a problem with the way leveling roulette has been designed and neither do I want it changed. If you have friends/fc, pull a party of 4 together and speed-run Aurum Vale or go grind fates or something.