It's a welcome change. All three of those actors are very talented, and were picked to star in Fringe for a reason. While the series is essentially a three person story, these other three can carry their own weight. In fact, letting Peter be believed dead for a little while might give them a chance to be fleshed out even more, and in that regard, I welcome the idea. However, seeing as how the writers made Olivia hallucinate Peter in the alternate universe episodes so that Jackson could keep starring every week makes me think that even if the characters think Peter is dead, he will probably still get ample screen time. I'm not asking for less Jackson, I think this is the best role of his career to date, but I would like a bit more fairness to Brown, Nicole, and Reddick.
That aside, I have no complaints about this season of Fringe. It's tightly written, wonderfully exciting, super suspenseful, and beyond creative. Check out Fringe, now airing Friday nights at 9 p.m. on FOX.