Juncker is a super European insider from mighty power Luxembourg that few people know and fewer people in the European voting process were ever exposed to. Elections are supposed to have a veneer of responsibility attached to them, yet there were many countries where people voted and have no idea who Juncker, Schulz, Verhofstedt, etc. were. When people were voting for the European Parliament, they were not voting for those individuals to be their leaders. They were voting for their respective national parties whom most of the people that vote for them don't know their European party affiliation or care.
Verhofstedt to me is the worst. He gets a challenge from Olli Rehn who Verhofstedt and a few of his backers don't like, so instead of actually having an election to decide who is ALDE's candidate/leader for the EP elections (God forbid people, politicians even, actually have to vote on who their leader was), they work out a backroom compromise so the party primary disappears.