Masaki Iwane is one of the chief animators of the anime, and he has a blog where he frequently answers questions and comments from people. Just a whie back, he answered two specific comments. From "Batman", it was a statement hoping that Team Plasma would appear, possibly near Dragonspiral Tower, and from "Suzaku", it was a question about what happened to Pierce and if the postponed TR vs. TP two-parter was meant to be his final appearance.
Iwane's answer's translate to:
1. "Possibly near Sekka City (Iccirus City), yes. Please look forward to Plasma Gang (Team Plasma).
2. "Only Dr. Seger (Zager) frequently appears presently, but....."
The "please look forward to Plasma Gang" is a big deal, as it's highly unlikely Iwane would say that if there were no plans for Team Plasma to return, as he's very polite and respectful toward his fans, and his "look forward to" type of comments in the past have been sincere.
And the "but...." trailing off to end his response to "Suzaku" about Pierce also indicates that Pierce may just make a comeback after all.
Anyway, I'm very excited about these responses. Thoughts?
EDIT NOTE (PLEASE READ): Slight alteration: "Possibly near Sekka City, yes." is actually said in regards to Batman asking if the "Brycen and the Holy Mountain of Volcarona" episode occurs near Sekka City, to which Iwane says it does. The "Please look forward to Plasma Gang" is said in response to him saying he hopes they show up at Dragonspiral Tower, which means they are likely showing up there (which is still technically near Sekka City anyway, so the point still stands.....)