Tokens should exist alongside RNG; not in place of it.

The good thing about tokens is you know it will never take you more than X number of runs to get something.
The bad thing about tokens is you know it will never take you less than X number of runs to get something.

With tokens + RNG, you get a chance for happy surprises.

That said, I'd rather go with the PSO system of it all being RNG, but everything having a chance to drop a different, useful, and (for the most part) desirable item.