It's a bit puzzling that the MX lacks MLU, considering that the KX has it and is basically the same mechanically.

TBH the ASA range isn't much of a problem. If I really wanted to shoot Ilford Delta 3200 in my MX or KX I'll just set it to 1600 then remember to crank the shutter speed up a stop or turn the aperture down a stop. Last time I used the stuff the in-camera metering (on an SF7) couldn't cope with the party lighting anyway, so I just set it to 1/60 at f1.7 and made sure I only pressed the button when people's faces had some light on them. The vast majority of the frames were fine after a little adjustment to darken and improve contrast.