I'm okay with a hybrid approach.while i do not disagree with any of your literal points i think there is a problem within party politics when the parties say 'we know better and will not go with our supporters (voters) choice and instead will impose our annointed choice via back room deals'.
While you are correct they have every right to do that, I think it is a recipe for failure in the following election, if it is exposed and the person pushed aside was the true peoples choice.
Yes we can agree 'the people' can and do make bad choices from time to time, but we must then also acknowledge the 'back room deals also make bad choices from time to time.'. What is the protection against the latter?
I think if you want 'the people' to support you in the election following you should, in almost all instances put their choice and opinions over those of the back room dealers.
I like having some of the trappings of democratic governance draped over the party. But I am not outraged that experienced elder statesmen of the party are given a big stake in the nomination procedure.