I, too, would love an alternative. But, as others have said, building the database would be a bear. You could get those of us that are specialists to help with certain characters (like I could easily do Duffy and Jessica), but characters like Tinker Bell or the Fab 5 would be monsters...
Things I have always wanted in Pinpics:
-A search function within an individual's Pinpics account.
So if I'm looking at WDWPINTRADER's trades, and want to look for their Tinker Bell trades, I can type in that keyword to search within their Pinpics ID. I'd also love to be able to sort my own stuff, so if I wanted to print only my Jessica pins, I could sort then print that way. Speaking of which...
-Better/easier printing options
-Tagging system
-Like you said, a better opening page. I want to be able to get to either "My Pinpics" or a profile page that has all my links within one click.
-A simple, but stylish Profile page. Allows easier access to "My Pinpics", e-mail and contact info, maybe somewhere to talk about how you like to trade. You could even throw up a note if you're taking a break from trading so fellow traders will know. Also, PMing.
-Perhaps a sub-system or sub-gallery for APs and PPs, just so we're not looking at the same pin a gazillion times over
-A priority ranking would be nice- like, marking a pin as high, medium, or low priority for you, and maybe Grail. I think the new Pinpics has something like this, but I haven't been on the new site, so I'm not sure how it works. I have mixed feelings about this- it can help show people's priorities, which I've had issues with before...but it's also not super important in the actual functionality of a site like Pinpics. And some traders would abuse it, I think...
I think there were probably other things...if I can think of them, I'll drop them in here.