I agree, I also wish to seem more incentive for members to join and a bit of fun for achievements. Obviously the tasks were created to infuse some interest for members. I remain unconvinced that that worked, but I might be biased as I find them rather boring and they have created conflict here and there in the org (completing tool ship and repair tasks for example). The animal birth tasks for orgs are quite nice but seem to be rather rare and we have no control over it.
The management of the org remains a problem. Donations for fundraisers are hard to keep track off (much better on the farm), you cannot send messages to all, and org mail is not separate from personal mail.
something easy to do is provide a toke of accomplishment for org members when leveling up. It keeps showing a message, "your org has leveled up ...", but that just makes the "so what?" more glaring.
I was thinking of something like donating challenges that then has an actual return for org members, for example, increasing the % for breeding in members' zoos for a few days, or chances at certain sales of the donated animals.
a problem in the org is also in the progression of the game for bigger zoos as points become less important and zD requirements increase (I am in almost constant savings mode now). With that the importance of the existing benefits go down and costs increase.
Just a few thoughts, I am sure there are tons more and better ideas how we can make org life more attractive.