Do larger planar speakers produce more accurate sound?

Large planar speakers are the only ones that can reach low frequencies. Little ones with dynamic bass drivers suffer from lack of cohesion through the audio spectrum. Little ones by them selves simply lack bass.  
 

I've owned two pair of planar speakers, Apogee Caliper Signatures back in the 1990s, and Janszen Valentina P8 now. The latter are hybrids.

The Apogees were more impressive in the sense of a larger than life image.

The Janszens are more flat (very flat!) in FR, and the dynamic woofers are extremely well integrated. So I prefer them. They have relatively small electrostatic panels.

@Corelli, what dynamic speakers are you using now?

The KLH Nines (which apparently nobody here has owned/heard) have excellent dynamic range and bass impact - even when used in single pair configuration! They were designed by Roger West (Soundlab) and Arthur Janszen back in the early Sixties. The Nines beat the Quads in the above performance areas due to larger surface area and power handling. Janszen sells restored pairs at very reasonable prices.

I can speak from experience, having a pair of KLH Nines in use since 1992. I used a variety of amps with them, including Bedini 25/25's and Futterman OTL's. With the power amp section of the Carver Receiver (125wpc) they had floor-shaking bass power!