I watched Civil War again because my brother got it on DVD, and I must say, everytime I watch the film ilike it a bit more than the time before. I can safely call Zemo my favourite MCU villain after Loki.
Same feelings. Though Zemos plan is quite far fetched and makes not a lot of sense, his main goal, outcome, motivations, history etc. make him a wonderful, unique villain in the marvel universe. I also consider (lower down the list though) Alexander Pierce to be a underrated villain.