You are able to click on troop icon and know who donated the troop. Especially for clan wars, we ask for the best troops. People troll and donate the wrong troops on purpose. If we were able to see that information, we would know who to kick. It'll also be great on regular donations, so we would know who to thank.
For leaders and co-leaders; they are able to delete troops, for everyone. So if they see wrong troop, they can trash and replace them after. In a stable clan, co-leader status are given to people who you trust, so I say we give that privilege to co-leaders & leaders.