My best to you, Mike!
It is no surprise that 4E is both revolutionary and divisive... these tend to go hand-in-hand. From here on out it is likely that the game will continue to be this way and unlikely that it will return to the simplicity of the earlier editions. Anyone familiar with the financial realities of RPGs knows that new editions bring an injection of revenue and that too much similarity slows revenue. Quality is always important, but there must be innovation to stimulate revenue. One revolutionary aspect of 4E is that it extends the ways that a company can publish new material - in theory every sourcebook can feel like a new edition and raise much more revenue than the RPG sourcebooks from other editions or companies. This makes it unlikely that a new edition will be created for some time, and also more likely that it will resemble 4E when a new edition does come out.
What Mike will bring, first and foremost, will be his abilities as a manager. It is very difficult to manage a group that has creative talents. Creators dream and scheme and managers control. A good manager knows how to provide the creative outlet and encourage open thought while at the same time maintaining discipline and focus. You want the minds to be open but the work to be defined, on-mission, on-time, and on-budget.
With 4E WotC changed to how it published. The mantra early on was clearly about setting-independent product with just two products for Eberron and FR. Single race or class-specific books were anathema. Somewhat surprisingly, it has tweaked those approaches this year. From just two books for FR we know see several products for DS. We see books for the Dragonborn and Tiefling. From MP2 we skip DP2 and now switch to Essentials. It is hard to know what these changes signal. Was the model in need of a tweak financially? In a big way, or in a small way? Is Essentials a clever attempt to make the game more popular with the new crowd I see (6 tables worth in my city at D&D Encounters games)? Or, is it an attempt to prevent the splatbook boredom that hurt 3.5? Are revenues sagging drastically, or is this a step taken early on, before revenues dropped? Do the layoffs signify more financial bleeding, or do they signal an attempt to stay fresh and continually bring in new talent and explore new directions?
Mike likely has the answers to these questions and now needs to take the right managerial steps, even exploratory ones, to resolve the issues. We can only wonder whether Mike favored the earlier model or the changes brought in this year. And, of course, we can always wonder about why Andy left.
Surely, Mike's personal view on D&D will matter. Any manager must approve what they see before them. Of many options only some can be followed. And, at times, they must speak to what they desire. In both cases, those signals transform what others will design. His will not necessarily be the loudest voice, but it will be the guiding voice if he is an active manager.
Mike knows the game well. He stops and talks to gamers often. He gets how people feel. I am not concerned that he will be unaware of how gamers feel. He is also a capable game developer, arguably amongst the finest. I am not concerned about how he will develop D&D, even knowing that he may not develop the game in a way I would prefer.
In my opinion, the most interesting question will really be around management and financial performance. While this edition seems to have been designed much more cleverly for revenue, and while the staff seems to be happier than in many eras, the layoffs and the inability to deliver Adventure Tools suggest prior mismanagement and financial struggles. I truly hope Mike is the guy that can manage these problems away. In all likelihood, it would be done by hiring experts in those areas, but also by making hard decisions. We all want a financially strong and smartly managed Wotc so they make great products we want to play.
My best to Mike. This must be a really exciting opportunity but also a very challenging time in his life.