Could be. But the war wasn't ever -that- one sided. The momentum swung back and forth a number of times. The Federation and Klingons managed to hold the line and take DS9 by themselves. Betazed falling... unfortunate but happens. Sisko indicated it was more because the Fed fleet was out of position than sheer overwhelming force though.
The power disparity couldn't have been that great because when the Romulans joined that tilted the balance of power to the Federation's side and they went on the offensive in Chintaka. It took the Breen joining up with the Dominion for them to get the initiative back and even then that was mainly due to their super weapon which once countered, the good guys were right back on the offensive.
Without bring tricked into having a personal stake in the war... from the Romulans perspective their two greatest rivals are slugging it out. Yeah... too bad.