I just got word that WebTrends 8.1 is coming within the next 4 weeks to WebTrends on demand. I expect that it will be also available around the same time as an upgrade for people who have a local installation.
From the noticed I've received they are promoting better integration with the Marketing Lab 2 and WebTrends Dynamic Search. There is no mention of what enhancements or new features will be included in the analytics software upgrade.
Stay tuned for more information on this WebTrends upgrade as I get it.