From 1.69 up to 1.80 is a pretty big leap in firmware numbers, and it can't have taken Sony coders that long to update the PSOne engine (even the compatibility testing wouldn't have taken this long), so what else could the company be packing into the next firmware update?
Number one on most people's lists would be an improved browser, with Flash support (not likely), and better integration between the apps (Facebook, Twitter and YouTube) with the browser.
Number two would be PS2 support, Sony has discounted this notion in the past, but software developers just don't sit still and gamers' needs move on at a frightening pace, as Metal Gear HD proved. An alternative could be the Gaikai service Sony brought to deliver games without the technical hassle and huge downloads (but, we're a bit early for that). on the plus side, Sony would rake it in selling extra memory cards and have 2 million plus more users capable of paying for PS2 games.
Having more apps open while you game would also be a good addition, allowing you to drop in and out of sessions. Also, getting rid of having to press "Start" to launch each app would be more than welcome. What else would you like to see in the upcoming update?