A very good point!
I've been away from garages for a few years now, and I guess these are all into 'worthless bangers' territory but the really bad ones were Renault Laguna 2, Megane 2 and Scenic 2 - all had catastrophic faults baked in all over the place with clutches, DMFs, ECUs, general electrical stuff, handsfree key cards, EGR valves, body control units and handbrake mechanisms depending on which engine you had the misfortune to be dealing with at the time. Then there are the headlight/sidelight bulbs on the Megane... The fact that window regulators and ignition coils were basically a consumable item was a mere sideshow when compared with the impending mechanical doom likely to be round the corner. A colleague ignored all the advice and bought a top spec Laguna 1.9dCi as it was a grand cheaper than a Mondeo. Within six months it ate that in repairs and in not much over a year it needed a body control unit, ECU, clutch, flywheel, EGR (twice, I think) and other sundry bits. The alloy wheels were also made of cheese and buckled if you looked at them in the right way.
I'd also like to preemptively nominate any of the PSA 'Hybrid4' models for this category in the future. Most of them will have covered plenty of miles, they're hugely complex, have the 2.0 HDi engine and an automated manual single clutch gearbox and frankly I just wouldn't trust one.