Speaking to VideoGamer.com in an interview from Leipzig Games Convention last week, Wrath of the Lich King lead game designer Tom Chilton said that it may be possible that constant expansions "keep the game looking fresh" and that high tech has never been a priority for the developer.
When asked how many expansions Blizzard could make for WoW before a series reboot is needed, Chilton replied: "It may never be necessary. It may be possible that just through constant iteration we're able to keep the game looking fresh enough. I mean for us it's never been a priority to have the highest tech game on the market.
"For us usability is a lot more important. We want to make sure that our game runs very well on low system specs. We want to make sure that our engine supports our stylised look. So for us it's really more that kind of iterative improvement works a little bit better for us."