Foreign signals intelligence is the whole point of the NSA [1]. The only reason their spying on domestic traffic is controversial is that, unlike purely foreign traffic, there is a history of abuse of surveillance for domestic political purpose which has produced both laws imposing limits on and public expectations of restraint with regard to domestic surveillance.
So, no, the NSA spying on purely foreign traffic with no domestic nexus wouldn't be "one of the biggest claims so far", it would be exactly what the NSA exists to do and a non-issue.
It would be news if the NSA wasn't spying on purely foreign traffic, not if it was.
[1] From http://www.nsa.gov/ : "The NSA/CSS core missions are to protect U.S. national security systems and to produce foreign signals intelligence information."