It would be cool if there was some way to tell before setting up an account what your site's weight would be on the network. I have a few smaller sites that I'm debating putting on the netork, but don't know if I could even get a beneficial weight out of them. I'd love it if there was a way to tell without setting up the account. It would also save a bit of resources perhaps from people that sign up, see that their weight is minimal, then take the ads off their site and leave a dead account on DP's servers.
I agree, it would be good to see what your weight would be before joining. However on your second point you can join the coop with all those sites then combine all those small accounts and point the combined weight towards one keyword. I also assume people with small weight can get together and consolidate all there weight pointing it towards one keyword....taking turns sharing the weight two months on two months off....whatever.
you can also go to the KW tracker and get the pages indexed by google of your site. Your weight = Pages indexed x PR x # of ads SO if you have 1000 pages indexed, and a pr of 5 and run 5 ads - your weight is 25,000