Fabrice Cambounet's developer diary can be found on the official forum. It is a short internal Q&A (who on earth answers questions in a diary?) about the alternate upgrade concept, the main feature of the Tribes of the East expansion. But there is more:

"There are many improvements to be expected ! We have been working extensively on the storytelling tools. The jump in quality is clear from H5 to Hammers of Fate, and you can expect the same kind of quality leap from HoF to Tribes of the East. This is critical to deliver a perfect ending for the story arc covering all of the campaign chapters started with the demon invasion. A small but interesting point for the fans is the addition of an adventure building that will allow the heroes to redistribute their skills. Another important point is of course the inclusion of the Orc faction, with their own special blood rage ability "

In other news, old maps are also being redistribued. The contest winning maps can be found in this thread, courtesy of Acheval, and the original maps of both Heroes V and its expansion are hosted at Age of Heroes. Now you can easily edit your favorite multiplayer map in time for your next hot seat session.