In a recent thread, esper mentioned that one could gain sainthood by doing nothing but logging in and vote on other nodes.

I'd say that it's a lot worse than that. In theory, one could gain sainthood just by logging in and downvoting anything one sees. I think this is very bad. I've mentioned this before, but this time I'll mention it in a meditation of it's own, hoping for a broader audience.

I really think one should not receive any XP when downvoting.

Downvoting has it's reason in selected cases, but I think the voter should pay a price when downvoting. And that price should be the knowledge that you cannot gain any XP when downvoting. tye once proposed that one should risk loosing XP by downvoting. I think that's taking it too far (at least for the moment) but gaining XP from downvoting just seems terribly wrong.

This would mean that to gain XP from voting, you must vote ++. Which would somewhat indicate an agreement with the author of the node. And would make it impossible to become a Saint only by downvoting.

I believe that someone frequently downvoting is probably doing personality voting, whereas someone that is only exceptionally downvoting is convinced the node should be downvoted on it's own contents and is ready to pay a small price for it.

XP should be earned by writing good nodes and by reading and voting on good nodes.