I have this same opinion too, whenever I go to a jamming studio, I see 9 out of 10 gtrist suppress their mids .

I think becasue boosting the low and higs sound 'heavier' which is not always false. Iused to have such tone settings before and I could NEVER get the type of tone of my heros like Gary Moore, Ritchie Blackmoore, Jeff Beck....you know, the usual suspects ;)

Then by 'accident', I played on an amp with the mids turned up and the low& high down to about the 3 to 4 level. I find it a little hard to cut through the strings initially but after a while, I finally got the sound I wanted. I find the the mids has its unique 'bass' or bottom-end quality in an unique way. And it made my playing sounds cleaner than it actually is.

When I had a parametric EQ previously, I always "screw" with the settings like:

Lo: 2kHz / +2dB
Mid: 2.8kHz / +3dB
Hi: 1.6kHz / -2dB

Basically, just jumble up the frequency setting and forget about the lo/mid/hi classification.

As you can see, I am just a regular "guy-in-the-middle" :)