I think my least favourite dryer design was the Hotpoint Reversomatic by mum had, which was a "pair" for with her X2000 washing machine. It had the heating element at the front, covered by a half doughnut shaped metal panel the width of the plastic drum, and the diameter of the porthole was a fair bit smaller than todays 600 mm wide machines. So I often burnt my arm on the extremely hot panel, checking if the washing was dry, and pulling the filter out, which was at the back, without leaving it long enough to go cold.
It also had the two worst, over complicated button latch mechanisms I've ever come across, one for selecting half heat and the other to enable a buzzer that would sound after it had finished and at the end of each extra crease care tumble. For some reason, rather than sourcing a simple push button with its own built in latching mechanism, they used momentary action rocker switches, that spring back to the off position, mounted in a rear panel, with metal stalks riveted to the front of the "on" half of the plastic rocker, and with the plastic button and a pin attached to the other end. And each had a thin brass plate with a slot pattern cut through to latch onto the pin. The slots would get closed up with use, so I'd often be taking the front facia of the control panel off and using a screwdriver to open up the slots.
The element was a length of thin wire attached to thin asbestos string, a bit like the outer section of a spiderweb, when it broke it would short to the case.
One thing going for the design, was the fan at the back drew the room air into the metal cabinet which was sealed up with putty and foam draft strip, so being under positive pressure, you would never get any lint escaping into the case or element.
The tumble dryer I have now, was one of the hotpoint / Indesit ones that were recalled as a fire risk (about 11 years of production), after Whirlpool purchased indesit, due to the risk of fluff getting trapped in the rear foam seal and falling onto the element. Before that, I'd pulled a couple of large black dustbin bag fulls of fluff out of the case when I'd replaced the rear drum bushing.