Bolero:why can't my system reproduce snare well?

Consider taking your source recording to a trusted dealer for a test on their flagship rig? You might even be exposed to your next step in this fabulous hobby.

The stock Mac tubes are OK (better than when the first of the current version 275's first came out in 2004) but you can do way better. Nevertheless, they should still reproduce snare drums well, and unless there is something terribly wrong with the ML's, like loose diaphragm(s) that's not it either. I would try and find other recordings with similar material, unless you can say you've heard this Bolero on other systems and it sounded great (which you didn't say ;~)

I use a 275 w/ my ML's and it sounds fantastic (see my system)

Are you paying attention to vibration control of the speakers?
Upon what are they resting? I have found this issue to be important on
my Prodigys. Play with this aspect, and it might benefit the whole sound spectrum...

Also... are all of the screws securely tightened? How about toe in of the speakers, their position in the listening room, and your position when you are listening to music? Raising my seating height makes a difference, for me!

The recording quality is not the question, but the mic placement. An orchestral recording with minimalist/distant miking may give you the sound of the snare drums that you are reproducing - try a nice Jazz trio

I second the comments about recording technique and quality.

Also, to be sure that nothing simple is being overlooked, are you using the 4 ohm taps on the amplifier? If not, that is undoubtedly part of the problem.

Also, given that the impedance of the speakers descends to very low values in the upper treble region (as is typical of electrostatics), if your speaker cables are particularly long and also have highish inductance per unit length that could be a contributing factor as well.

Regards,
-- Al