Funny how people are different. Due to injury I recently started riding on flats again and couldn’t work out why the DMR V11s I picked up felt so bad when everyone else seems to rave about them (as far as plastic pedals go). After reading an NSMB article I tried some oneup composites and they feel great despite being roundly panned in the media. The difference? The oneups lack concavity and the way I place my feet, with the ball of my foot well in front of the axle, planar pedals work better than concave.
So from my perspective I think that using concavity as a judging criteria for pedals is a bit like complaining that clothes don’t fit! They aren’t wrong, they just aren’t designed for you, let someone who can use them evaluate them. (Sorry, spent ages looking at pedal reviews and every flat pedal seems to have “concavity” being the overriding criteria for judgement……….)