I think the open primaries are not a big issue. If you really want to prevent a trump or a bernie proportional is the way to go then require a majority to win. Exactly like what the dems did with their party. The superdelegates are just gravy. If they judged bernie was a real threat at the start you could just fund someone to his left and split the vote multiple ways ensuring no one hits the number and letting the establishment (superdelegates and/or contested convention) decide everything.
Bernie never really had a chance. The dem machine was too fine tuned for him to win. If Bernie ran as a republican and trump a democrat then Bernie would have won and Trump lost. The democrats are just better at keeping the power in the hands of their elite. Meanwhile in the Republican side YEB! got massacred in the 3rd contest.
