Liseberg has announced Quick Pass as "the biggest news of the year"!
I couldn't find it in English but for my fellow swedes here is the page at Liseberg's web page.
A short explanation; anyone that buys a one day unlimited pass will be able to reserve the five biggest attractions in the park at any free time. This means that, in connection with the purchase, you'd have to decide when you want to ride a ride. You can for example book a seat on Balder at 12:00 and later a ride on Flume Ride at 13:30. If you are there at the given time you can walk past the entire line, sit down and enjoy the ride. Only one time on each ride is available for each day pass. The five attractions which offers Quick Pass is; Balder, Kanonen, Lisebergbanan, Flume Ride and Kållerado.
As already mentioned, the say that this is the biggest news of the year; not the only one. But they still haven't announced any new rides or other attractions... I really hope they will!