Legend's Glen Dahlgren made a post to the official Wheel of Time message boards, mentioning that there aren't any plans for a retail add-on pack for Wheel of Time, but there are plans for a "point release" that will amongst other things, include deathmatch (arena) bots. Here's the scoop:

There are no concrete plans for an expansion yet, although we are working on the point release/expansion to be distributed (for free) shortly into the new year. This should include a few new maps and features, and arena bots!