After the recent 2.1.4 sandbox update, shards received a nerf that dropped their max super gen (A decent idea, seeing how overpowered the were before), but they also now only regenerate super energy on hits. The regenerating super only on hits essentially makes shards almost useless since most adds will only take 1 hit from a knife and the knives track in groups, making it nearly impossible to get more than 1/4 of your super back from anything that isn't a super tanky ultra.