Honestly, the incentive issue is the least issue, because you can simply make sure that whatever currency you use to make the items buyable is primarily rewarded from the roulettes - with a bonus if you queue as adventurer in need.
The incentive is clear - make yourself available for all dungeons in the roulette to get the items you want and speed up people's queues if you want to speed up the process for yourself. The downsides are the generic reward downsides (Every external reward has downsides). That helps everyone who wants to do a specific piece of content, because people are no longer pointlessly queuing for specific dungeons to get the glamour gear from there, they fill the queues wherever needed. Moreover, that would ensure that people don't just farm the stuff they want unsynced and solo, which doesn't help the queues one bit.
On that note, lore rewards should also be adjusted - aetherochemical research facility should NOT be more efficient for lore farming than the roulettes especially when the roulette reward can only be claimed daily. That's just a bad incentive and makes the lore-grind of the anima quest not only a lot less effective at speeding queues for non-ARF instances than it could but also more monotonous to boot. In general, you want as few people queuing for specific things and as many people queuing as filler as possible to speed up queues for all content. You can have 40 tanks, 40 healers and 80 DPS queued up and make 40 dungeons or 20 trials with that if all are willing to fill. If everyone wants a specific dungeon/trial, in the worst case you cannot make a single group with that. If anyone asks you what kills content, that kills content. You can also ask PvPers about GC restrictions - same deal. They've been begging for a filler option or GC restriction removal for years.
So yeah - that is not an issue. The main issue is balancing reward and effort and for that, you can simply refer to the statistical probabilities. If something has a 10% chance to drop, you require 10 roulette runs worth of currency to get it. Doesn't change much in the grand scheme of things, it only destroys outliers. That's plain math. And if you're feeling lucky, you can still just queue for the particular dungeon instead of filling needed spots. I personally wouldn't do that, because even if I was guaranteed my item after 10 runs of the same instance, I'd still find the variety of roulettes more fun. But that's just me.
So yeah, the only issue I can somewhat understand is currency bloat - which can be resolved by simply using the damned currency tab for currency for a change >_>
Then again, I am biased against RNG, as I already said. I hate it with a passion. So it is healthy to check if my arguments have logical flaws I have missed in my rage. But yeah...I don't really see the issues others are seeing.