Larger usually sound nicer (not saying that’s the same as ’accurate’). They’re not so soon stressed to their limits to produce a certain SPL, they operate more ’relaxed’.
Larger size is able to create a wonderful soundstage, almost 3D, and with height involved. On my maggies, with eyes closed, subtle sounds like a cymbal or a shaker, can seem to originate top left, or half height right, very funny. It can be imagination, but when playing the same song again, it again is the same experience.
You didn’t want to talk about base but of course that’s a great part of sounding nice, and of ’accuracy’.
However, it’s not just size, there’s also the crossover filter, with magnetostas the magnets, with electrostats the electronics, the build quility, and ... important ... the moving foil. You’ll seldom see a planar the size of a door ... at some point it becomes troublesome to keep the foil tight and moving as a whole without ripples.
’Accurate’ need not translate to ’sounds nice’. Some people love equipment that’s measurably less accurate.(think vinyl or tube amplifiers).