At a individual level, sure. At an international level, though?
People are always willing to take risks to wage war; how come so few are willing to take risks to wage peace?
Projecting to your opponent an over-eagerness to avoid war is probably one of the more surefire ways of increasing the risk of getting one.
No one has said that the Dominion has an eagerness to avoid war.
But if the Federation had offered the Founders the cure? This would have been a decision made from a position of strength, not appeasement or fear. (Remember, everyone already knew the Dominion was going to lose the war by the time of "Inter Arma Enim;" Section 31 was even preparing for a post-Dominion War conflict with the Romulans.)
Worst case scenario? The Founders, long believing that the Solids of the galaxy cannot be trusted, would see the Federation saving them from certain extinction, in spite of their war of aggression against the UFP -- and demanding nothing in return. It might not end the war, but it would almost certainly undermine the ideological basis for the Founders' xenophobia. It might lead neutral Alpha Quadrant powers to side with the Federation, and it would plant the seeds of change in the Dominion body politic. And in a best-case scenario? The Founders would call off the war from gratitude.
It would be worth the risk.