Unless they are leaking, your calipers are fine. Uneven pad wear is not an indicator of failure in single piston calipers. On those cars, accelerated outer pad wear is not uncommon. Causes could include inconsistent pad material, improper break-in, or contamination of abrasives through the wheel.

The shuddering could have a few different causes as well. Typically rotor warpage doesn't exhibit itself intermittently. It can be speed dependant, though. Is the shuddering felt in the brake pedal or the steering wheel? If it is determined to be rotor warpage, make sure that the technician cleans the rust scale from the hub before installing new rotors. This step is often skipped. On cars with your mileage the scale can accumulate enough to cause rotor warpage.
If the shuddering is truly intermittent I'd be suspicious of worn steering and suspension components. When everything is worn "just some" under certain circumstances those extra clearances can all stack up and cause erratic behavior including oscillations.

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90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff