Romantic and quiet are hard to find anywhere at WDW.
At the Disney restaurants there are swarms of kids--often acting out.
At the Swan/Dolphin, there are swarms of conventioneers--often acting out.
That said, we find Artist Point, Citricos, and Yachtsman to be the most "quiet" spots of the Disney spots.
And Blue zoo and Shula's in the Swan/Dolphin.
BUt on any given night, all bets are off for a truly quiet or romantic dinner at WDW.