This rumor sounds a little bit like wishful thinking.
First off, last I heard, statements made by Paramount suggested that its executives believe the franchise is simply losing its fans. There was never a hint that Berman or Braga weren't living up to expectations (although that's probably not the sort of thing they'd air in public.) Still, if it believes the franchise is losing its fans, it seems unlikely to invest in a new series.
Second, its extraordinarily unlikely Starfleet would rely on the Klingons as its sword arm. They aren't reliable, or maybe a better would would be predictable, enough. Internecine conflict could turn them against the Federation.
I suspect that any future series will take place after the Dominion War -- significantly after. Maybe even after the Second Dominion War...