this announcement, we're getting another version of RuneQuest, the sixth edition, in 2012. This edition is being written by Lawrence Whitaker and Pete Nash, the gentlemen who gave the world Mongoose's RuneQuest II. As you may remember, RuneQuest II, under the name Legend, will continue to be published by Mongoose and the FAQ on Whitaker and Nash's website states that there is "a very high degree of compatibility between the two games." There will be differences, but, from what I can tell, those differences seem more about coverage of content than game mechanics.
So, if I find myself in the ironic position of many an outsider to the old school D&D world asking the question, "Do we really need another version of RuneQuest, especially when this new one is designed by the same people as the previous -- and still available -- version and is largely identical to it?" I sincerely have no idea. My suspicion is that this sixth edition is a consequence of the severing of the ties between Issaries, the owner of the RuneQuest name, and Mongoose. In the announcement linked above, Issaries president Greg Stafford talks about RuneQuest being a "highly respected brand" with a "good name" and reputation. That suggests one possible motivation for this move. Likewise, I understand that Whitaker and Nash ceased working with Mongoose on RuneQuest II after a certain point, despite their products being considered among the best for the line. This new arrangement may simply allow them to pick up where they left off without interference.
Not being primarily a player of RuneQuest or indeed BRP generally, I'm not sure what to make of all this. It's definitely interesting and, were I a player of RQ, I'd likely find this latest news equal parts encouraging and baffling. Regardless, this is probably one of the most exciting times to be a player of BRP-derived games since the early 90s.