I found a few quotes from newspaper articles that may be of interest...
1. Yes, Jon Vitti (writer of "Cape Feare," "Lisa's Substitute," "Mr. Plow" and other classics) is definitely back with "The Simpsons." In addition to the episode mentioned in the NEW YORK TIMES article, I found a description of another upcoming Vitti-scripted episode. Here's a quote from Robert Pinsky, former poet laureate of the U.S., about his guest-starring role in this ep:
"I'm cast as a character named Robert Pinsky, who's a poet. This guy is a self-important jerk. I brag about the White House, how much the president likes my poems, I mutter to myself, congratulating myself about how the audience is in the palm of my hand. I start reading my poem, 'Impossible to Tell,' from the podium at Springfield's college. Lisa is pretending to be a college student and she goes on campus with new friends who think she's their age and they go to the poetry reading. Lisa appreciates it, but she's just thrilled to be on a college campus."
So that's two Vitti scripts that are in the works. I'm assuming he's back as a "consultant," like Swartzwelder (i.e. someone who just writes scripts rather than getting involved in day-to-day production), but it's good that they brought back one of the top writers from the glory years.
2. Executive producer Al Jean (another top writer from the glory years) had this to say about how Homer will be characterized in upcoming episodes:
"Homer, over the years, has gotten stupider. We're trying to smarten him up. In the beginning, he was more angry... I can't say he's getting smarter, but we're trying to make him not as stupid."