At least these aren't outsiders being brought in but simply existing staff members getting promoted, so hopefully that's a good sign that not much will change. (Just reduce Herbert's presence, please. That's all I ask.) It's usually not good when a brand new person is brought in out of nowhere and made the show runner.
I thought the show was fine already. Oh well, this news is OK with me. But there should be new showrunners for The Simpsons (I mean, The Simpsons are great, but I think with new showrunners, the show will appeal to fans again.).
You're right. The show won't get a radical make over, Seth MacFarlene is still the main dude afterall, but there will be changes. Everyone has their own idea of how the show should be done. So, the new showrunners will be injecting more of that.