LeCellier is way too crowded and the tables are too close together. IMO, it could never be considered romantic.
As for CG and Jiko, well CG after the fireworks. Before, it's too insane with noisy kids running everywhere. Jiko, may be a safe bet, but only very very early, or very very late.
Beyond that -- and if you insist on a restaurant that is on the dining plan, we've had nice dinners at Artist Point after 8:30 p.m. When we were at Citrico's it wasn't just noisy it was an crashingly loud. The tables are not terribly well spaced, but again you could probably do okay there if you go late, after 8:30 p.m.
As for 1TS, really, none qualify as romantic really. We find if we get a booth at Wolfgang Puck, that can be nice. Also, we like Portofino, although I'm not sure it's on the dining plan.
Brown Derby (a 2TS restaurant last time I checked) has always been a zoo when we've been there; perhaps because they offer the Fantasmic dinner/show combo. Plus, the grapefruit cake, which used to be delicious, is now made offsite and kept frozen and so not worth the calories.
Chefs de France has tables so close together, I felt like I could sit on the lap of the guy at the next table and not be much closer than we already were. Not romantic at all unless you figure you're out with your dh and having a blind date with the guy at the next table all at the same time!
Same with San Angel Inn. The Epcot restaurants seem to have solved their lack of space problem by simply doubling the number of tables in the existing space. Not romantic at all.
One exception might be Marakesh in Morocco, which often is not full. And, the belly dancer is fun to watch.