In any system where you select multiple candidates (including approval voting) you'll get horse-trading between parties before the election. Basically, the mino

In any system where you select multiple candidates (including approval voting) you'll get horse-trading between parties before the election. Basically, the minor parties say "if you adopt this policy, we'll direct our preferences / recommend voters approve you in our campaign leaflets". And then controversies over "you're doing a deal with them?" It's really quite hard to create an electoral system with no distortion, because whatever you put up gets gamed.