While I doubt the run from character level (clvl) 1 through 13 provides much insight around this topic, I am wondering if anyone simply noticed the effects of experience ramping due to clvl versus monster level (mlvl)? For example, during the open beta weekend, I'd run the SK dozens of times and there'd occasionally be a very low lvl character in party (i.e., clvl 1-3). I wasn't able to tell, however, if that character was seeing improved exp gain rates.

Clearly, we don't have the play time to establish something like this yet: http://diablo2.diablowiki.net/Experience_Chart, but it's worth noting if there have been any observable effects in the limited experience the beta has provided.