No, I don't think so. I think they would have kept it at 1 if people had not asked for more. However, now with them expirimenting with CPM, I doubt they will be increase the number of ads.
Anything over 3 does get to be overkill, and starts to look "spammish"
I think they might alter the rules somewhat to allow different sizes and types of ads (As they come up with newer types of ads, assuming the 'adlinks' option stays around).
-Allan