red lucky balls can be bought with amber tokens
That is not a viable option for low level players (and certainly wasn't at the time). While Tramis Dungeon parties do exist, most of them are being run by high level players on their alts and are running it together anyway. Hardly anyone hunts down Alastor Minions as well.
Yes, you can trade down higher level tokens to Amber tokens to redeem the blue/red lucky balls, but that is still RNG. Someone could redeem a 100 of them and hypothetically still not get their desired cosmetic gear.
A "problem" I would see is a player downgrading their tokens to get the X amount of Red/Blue Lucky Balls needed to redeem a guaranteed Call Bell or whatever. The team can decide on the appropriate numbers for balancing as the numbers I gave were arbitrary. Or limit them to specific general lucky balls, since I can also possibly turn in an insane number of Dark Lucky Balls for guaranteed number of Meridian Rs.
They would still be in 4 seasons if my full idea were to be implemented. I think all lucky balls should drop in 4 seasons and drop at a much higher rate, and all be purchasable through the signs.
Quoting my paragraph of my personal opinion doing it via Four Seasons again:
Grinding general lucky balls in Four Seasons sounds like adding unnecessary hours for no reason on a weekend, ESPECIALLY single targeting. If I wanted more of Maroon Lucky Balls, that's a lot of hours I don't have spent on my free days. I rather personally aoe/grind or do something else.
Only time I would see this viable are for level 200 players across all their characters, but no one is that insane yet.