In order to save the class twice, we could do something like this (the classes below are just examples):
Unsaved:
Bard
Factotum
Wilder
Then, we suppose InnaBinder comes and saves the Wilder...
Unsaved:
Bard
Factotum
Wilder (1)
Then I go and save the Bard...
Unsaved:
Bard (1)
Factotum
Wilder (1)
And then, someone that probably exists only in this example comes and saves the Wilder again...
Saved:
Wilder
Unsaved:
Bard (1)
Factotum
The round woudl end when there is only one class that wasn't saved twice (even if it was saved once).
One rule that would also make it fair is that the same person can't save a class twice. With this rule we would be sure it's not a class that only that single person likes.
* these rules are just examples, I'm just suggesting them, although I really think they're good.
** I also believe we'll need another change in the rules when we reach around 7 classes, maybe Save Thrice. With 3 classes, we could probably start a poll.
*** btw, I don't believe a Cleric always outperforms a Druid... Clerics can't outperform the wildshape cuteness D: