An extra wheel spin every 2 levels up to a total of 3.
After that, the 3 wheels combine into a slot machine. You get 3 prices, plus a bonus if the prices match.

Going down even further only increases the chances of good stuff while decreasing things like sleep vials and 1* mats.

On first glance it seems fair, but at a deeper look; where's the real difference?

You want to punish people who ditch others, but would also punish people who simply don't have the mind/endurance to do long runs.

Yes, I know, you want group A rewarded, but group A getting more than group B means B gets less than A, and could feel punished for simply not having the time or ability to sit through more levels.

What's wrong with joining at the last second? Personally, if I have to go to FSC for whatever reason (every few months, for example to shiver for a friend who needs that mission completed, to help the expert out who does the real trip with him - also I got the last tokens for completing Ancient set that way), I prefer to enter before the last party button on D:27. Those that do all levels already get more; I get 1 token only.
The whole trip is just too long to always be the same; I got tired of it before I had the gear to try alone.
That strategy (me not wasting my time with those levels) totally has no effect on you or any random players at all. So what business of yours is it, for you to decide it's a bad thing?

For Arcade, I'd prefer it if I could do 1 level, come back later, do the 2nd, then at another time a third. (See my suggestion about the Fifth Gate.)
What keeps me from going past Basil is that by that time I simply don't want to play any more levels right then.

Missions are ok, especially those where just the first level is nice enough.

I don't know what you mean by reviving Arcade. Forcing people to go where they don't want to be is a bad thing. It wouldn't open more parties for you, only spoil it for people you likely never meet.
How would you know there isn't already tons of parties in the Arcade that just aren't open for randoms anyway?
I don't like people who think they have any say in what others 'should' do.

Your so-called drawbacks have not affected me in any negative way, so it certainly isn't universal.

I think in the end, for me it would depend on the size of the reward. Don't make it too big, and I would be content to have someone else get it for seemingly investing more consecutive time.
(Seemingly, because there's no effective difference between someone doing 4 levels in Arcade, and me doing 4x first level of Terminal Meltdown. Apart from me getting more loading screens.)

But I'd much rather see all loot you gathered only entering your pocket at the elevator. That would discourage ditchers. (We already have that with minerals...)