Jane this is in reference to idea:
You have dismissed this idea as a plugin issue. It is not. It very much is about WordPress core.
Look at your own blog and hit "NEXT" at the bottom. You will be taken to page 2, than 3 etc.
Another words CURRENT page is always 1, and as you add post all older pages get re-indexed.
Where in fact your oldest (1st post ever) should be on page 1, and posts after that should fall on pages in ascending order.
This way, if a search engine indexes your blog by page numbers (and it will as you have not specified rel="nofollow" on your pagination links) the index would be always right, where now your posts keep moving all the time against page numbers and are effectively never correct, unless the search engine manages to re-index all your pages every visit. This may be OK for 10 posts blog, but it won't happen if you have thousands of posts.
I have marked this "major" since this is a fundamental change to WordPress paging logic.
Think of it as of writing a book, as you progress your writing the page numbers increase.