You can implore, but I'm going to let you know that a line-by-line changelog won't be produced. It's honestly very, very difficult with our build process to generate one since the line-numbers would have to be manually created.
With that said, we should be able to at least produce a list of what files have changed... with that, you can at least do a diff and make sure that you've re-implemented the changes in the new release in you're 'older' release. I won't remember to produce one each time, but it's something if you ask for in the forums, I'm sure we could generate after a day or so.
Of course, the other option is to simply document the changes you make on your site and then re-implement them after you upgrade.
Either way, glad you've moved on to J2.5. It's much better, and we're excited to be dropping J1.5 development in general. It'll be very nice to have a 3.x release out soon as well!
Thanks,
Alex