I am an eBayer in Australia, and though I've never had Paypal related problems, I do agree that the complaints time limit needs to be increased. From the auction end time to when the item is paid for and shipped could easily take 14 days, and then usually 7-14 days for shipping, and there is nearly 30 days gone already.
Another suggestion I agree with that was made earlier was to align all the categories. It is frustrating to do a search via eBay.com.au for an item with 'worldwide' selected, and only get results from a couple of countries because the category numbers do not match worldwide. I then have to go US eBay (where most of the sellers are) or UK eBay and do a separate search, sorting through to find the sellers that ship internationally. The Advanced Search option of choosing "Items available to > [select country]" does not work well because many US sellers have "Ship to US only" set as the default, yet in their auctions state they *do* ship to Australia/UK/etc and list their international rates.
It would also be great if eBay could raise awareness of selecting international shipping destinations when sellers are listing items. I think many sellers are unaware that they can choose which international areas they will ship to, and are afraid they may have to deal with scam buyers from countries with a high rate of fraud. eBay should make it clear they can choose "safe" countries such as Aus/NZ/UK/EU to ship to.
I also agree with the above poster who said it would be a good idea to have an eBay tutorial/help page to show people how to fill out a customs declaration sticker or form, and that it's not scary paperwork, just a few lines that take less than 2 minutes to fill out.