I think we need to borrow the whole British parliament thing so the smaller parties have actual representation in congress.
Err, we are even more unbalanced - you should be looking at Continental systems like Spain or Germany for that. Our first past the post system means a party can win 40% of the vote and have pretty much total power.
Now our Prime Ministers can be removed by their MPs at any time, but if they can keep them on side and have a majority then they can pretty much do what they like. The smaller parties might get some representation, but there is usually fuck all they can actually do. PMs are domestically more powerful than your President in many ways.
Oh and Bernie Sanders will be 83 at the next election, meaning he would 87 by the of the term. Seriously? Can you really not find anyone who doesn't think electric lights are a cool new innovation?