It was difficult for me to leave the first couple of times. Now, I just open two windows, copy and paste the url from one to the other to leave feedback. If feedback is left right away, the threads don't get lost in the shuffle.
I, too, have had several transactions and not been left feedback, and I believe it mostly because some may get frustrated after trying it for the first time and just say "ahhh, forget it".
As far as making it better, I'm not at all computer smart, so I'll just say eBay makes it very easy to leave feedback. Maybe a detailed "how to" thread on leaving feedback.?.? ...