It is absolutely true that nearfield measurements don't tell a complete story about how each speaker sound in a room, but wouldn't you say that dipoles are in a kind of complex situation there because of added reflections?
Don't get me wrong, I heard MLs several times and I really like how they sound but strictly speaking wouldn't you say that speakers like Revels are providing more accurate in-room response?
The situation with dipoles isn't too hard to compare with monopoles.
Below Schroeder frequency in the bass, there is some debate to the differences between monopole, dipole and cardiod bass. In the case of the ML, it uses an enclosed woofer, so it's just a standard monopole here.
At midrange, the ESL exhibits really narrow directivity due to the large radiating area - equivalent to a woofer of the same size. What's somewhat unique is the sudden and complete drop off at 90 degrees off axis due to the dipole cancellation. This reduces near reflections, which is a good thing in general. What is somewhat more problematic is that in the case of the ESL, the membrane creating the midrange and treble is enormous, leading to very tight directivity. You may know that large drivers 'beam' at high frequencies. Well, if you keep going even higher they get downright chaotic. ML's curvature may help with this for all I know. QUAD systems after the 63 model had another means of radiating treble from a smaller part of the panel.
This would then be a very dark sounding speaker if it weren't for the fact that the power response is filled in with reflections, so there is a good amount of uncorrelated treble energy bouncing around the room. I would recommend placing ESLs far from back walls, but not adding any acoustic absorption to the back walls for this reason.
If you want all the advantages of a dipole, and real dipole bass, see the Linkwitz 521 (RIP SL). This has the advantages of a normal 4-way monopole system with smoothly falling power response, low distortion drivers and wide treble dispersion combined with the lack of sidewall reflections exhibited by dipoles.
It is true that they interact with rooms in very different ways, but the ESL is a poor and somewhat outdated vision of what dipole speakers can be. See the gainphile DIY projects to see probably the most advanced dipoles, which use waveguides for the treble.