Over time I have heard from people who speculated that the Romulans would be scandalized etc, maybe even go to war with the Federation, if they discovered what Sisko did. There might have been novels written that way, although I wouldn't know since I don't read them; I don't believe they're canon.

But the main problem with all of that, would seem to be, that Garak was right: it IS exactly what the Romulans would have done, themselves! So how they could be very upset with the Federation for doing it? And the results were certainly positive!