I don't care that Blogger has another solution, which could fill the same function for the specific case of Blogger blogs equipped with backlinks lists; the tool is useful in the wide scope of alerting people anywhere when others bring perspective, new ideas and / or thoughts to the mix -- trackbacks are good. Let's make them better and easier to use.
And why not couple this with a bookmarklet that lets you mark a section of text in a page, run the bookmarklet, and perform the trackback scanning of pages linked in that bit of text (or other markup), to show a context menu much like Book Burro's where you can tick the pages you want to trackback ping from the present location. While at it. That would be a truly worthy hack. (Or Greasemonkey menu command, if that's your preference. I personally find them a bit unwieldy as accessibility goes, though.)
Feed curiosity. Make it easier for others to hear your own ideas making out with theirs. That is mostly what creative cross pollination is all about. And it's good.