Your calipers may have been OK. The most common problem with uneven wear is from sticking caliper slide pins and/or lack of lubrication where the pad backing plate contacts the caliper.
When you install the new parts make sure that the slide pins on the new calipers are well lubricated and lide freely. Make sure that you also lubricate the pad backing plate wherever it makes contact with the caliper, especially any edges that tend to slide as the pad wears. You should be able to find disc brake caliper slide grease wherever brake parts are sold.
As long as you are replacing the calipers and need to bleed the brakes anyway, now is a good time to change all the brake fluid, fronts and rears.
