Hmmm - whilst there are no current experience benefits to partying, there are other benefits. These are in terms of cost, mainly. If you party with another player then you share the hits - and if you share the hits, you halve the healing (catchy sentence, huh?)
Obviously, in general theres no shortage of gold on Nanny so perhaps that's not a benefit that many really enjoy. From an administrative point of view, however, it's unlikely that parties would be improved to give even more of an advantage than they do now.
Whilst I agree that it would be very interesting to split experience on the basis of contribution rather than share allocation I think it would make partying to help out new players pretty redundant.
Perhaps a better means of determining shares would be a combination of Kenpo's suggestion with the current implementation. Each player could opt for high/medium/low shares and that would act as a multiplier to the shares given which would, otherwise, depend on the cumulative contribution.
Except....this also has a major drawback. The drawback is how you gauge contribution. Kenpo mentions HP/SP loss, damage etc and that's all well and good. However, it's tough to really tie in contribution for any particular adversary when it comes to "support spells".
A large amount of spells are cast away from battle. People retreat to an adjoining room to heal, renew wards etc. How do you acknowledge that contribution to the party efforts when it comes to the death of the creature next door? You're not in the same room, you're not in combat (especially in the case of pre-combat warding) and how do we really know if it's a "support spell" or just a needless creation of light?
I'm not a major party-player anymore. Circumstances mean that I'm often called awayfrom the screen for extended periods with little notice. It's good to see thought going into this kind of thing though - and excuse me for being negative but it's best to sort out teething problems with ideas rather than ignoring them. Perhaps you've thought of this already and have the answers.
Let's hope so.