In fact, the last time I talked about Primeval was in July, when I made a post as complete as I could about all that was known about the series at the time so far (which you can read here).
According to producer Tim Bradley, who spoke to SFX's Red Alert, since most of the main characters becane stuck in the Mesozoic era:
The ARC is under new management because the disappearance of key personnel has left Lester a bit stranded. So the old team is joined by new characters who deal with the situations that happened off camera between the two years. There’s this new character, Philip Burton [played by Deep Space Nine’s Alexander Siddig], who’s a venture capitalist, and he’s been brought in to finance the new ARC set-up. One of his main areas of interest is investigating the science behind the anomalies. He’s really filling what Cutter’s demise left – a bit of a gap in the scientific journey.Nick Cutter (Douglas Henshall) was somewhat replaced during series 3 by ex-policeman Danny Quinn (Jason Flemyng), who may be returning, although probably briefly, to the series.
Bradley also say that the tone of the series will remain the same as the previous three series:
The majority of episodes will give you what everybody seems to want, which is a sort of tubthumping crashing beast to terrorise you. I think all our co-financiers want us to keep making the better show, but the same show. We don’t want to change the appeal of the programme, or take it in a direction that makes it harder for the younger audience to enjoy. That said, we are trying to make sure there are a few more adult beats for people, and we do perhaps want to push the creatures being a little more visceral.There you have it! I'm really looking forward to the new season which should air in early 2011. Bring on more tubthumping crashing beasts!!