Caolan mentioned in bug 83588 comment 8 that code to center a slide/page in Impress/Draw happens when changing the slide/page, but i havent been able to observe this behaviour and it would be useful for this to work. This didnt work in 3.3.0, 4.2.6, 4.3.6, or master on Linux.
got reverted IIRC, there was some hate against it so I abandoned it
If that is the case, then i'll just close this.