Rear brakes are often more finicky due to the longer cabling run, but it's not as much stretch as it's flexing and compression of the housing that's the villain. To get things as good as possible you really need to take care with the routing.
I'm not so sure about switching to v-brakes would be of much help, they too rely on the brake cable entering pretty much in line with the brake arm. If you come at them from below you have to run a sizeable loop in the cable to get to the noodle, and those loops are killers for brake efficiency. A pulley otoh is reasonably solid.
Maybe one could use one of those flexible noodles to get a decent cable run with a perpendicular approach to a v-brake?
I worked on a mixte frame once where I moved the brake from the seatstay bridge to the "top tube" stay bridge, and whas then able to run the youke cable on either side of the seat tube. Wasn't ideal, but it sure beat the original setup.