Nationwide have always been charged a fee by VISA of something like 0.84% the only VISA led change is an increase to 1%. I think that from a marketing perspective it was good to offer fee free foreign currency transactions thinking this would net off profits made in other types of transaction. Perhaps Nationwide have analysed their customer base and come to the conclusion that many of us use our Nationwide Cards (and indeed our current accounts) exclusively for foreign transactions. It isn't that surprising that this would prompt something of a rethink.
Personally I think that there are many efficiency savings to be made at Nationwide but as I have the scars to prove delivering change in Retail Banking is not always a straightforward task.
Much as Nationwide piss me off they seem to be the best of a bad bunch here. I don't know whether others have also noted that VISA Debit transactions from Flexaccounts which are made abroad will also be subject to the same 1% fee.