In four elections the candidate who won the popular vote lost the presidency. In 1824 neither candidate had enough electoral votes to win and the house picked the president, John Quincy Adams who had actually lost both the popular vote and had the fewer electoral votes became president. The others were Rutherford B. Hayes (1876), Benjamin Harrison (1888), and George W Bush (2000). It could conceivably happen again this election. In the advent of a tie, it is conceivable that an electoral college delegate could change his or her vote to break the tie or send the choice to congress. While some states require that the member follow the state's popular vote, there is actually no constitutional or federal law making that vote mandatory.
The last of the amendments I would offer is an addendum to the oath of office requiring all members of legislative and executive branch to denounce all written pledges or sworn oaths that are not expressly in the constitution. This would make it an impeachable offense if while in office any elected official signed a pledge like the Norquist pledge. In addition we might also consider adding that every supreme court justice sever ties with any political party. No more Democrat or Republican judges although they would still be conservative or liberal, it could become a crime for either party to influence a Supreme Court Justice.
That said, having discussed four ideas for amendment: limiting campaign length, limiting money in the campaign, repeal of the electors and changing the oath of office, getting these done is incredibly difficult. An amendment must first be ratified by two-thirds of both houses or state convention and then ratified by three-quarters of the states either by convention or by state legislature. Congress may choose which method will be used. Of all the ratified amendments only the 21st amendment (repeal of prohibition) used the convention method. This may surprise a few presidential candidates who have said they would sign an amendment into law that their signature is not needed and has no impact on the ratification of an amendment. Only "we the people" have the power to make those changes and that is why it is so difficult to pass an amendment.
There are right now technically four amendments that have been ratified by congress but not rejected or ratified by the states. One amendment, the Corwin amendment, has languished since 1861 since it has no expiration date for ratification -- most amendments do. If it had been passed, it is doubtful that it ever will, it could override the 13th and 14th amendments which abolishes slavery and expands voting rights. It has only been ratified by three states. Since 2000 there have been 13 amendments proposed in congress. Everything from the repeal of the 22nd amendment (limiting terms) to the elimination of the electoral college have been proposed. Few actually make it out of committee.
There is one other way to get an amendment than sending it through congress. Two-thirds of the states may apply for a national convention to amend the constitution. Once the convention meets, the amendment must still be ratified. Passing an amendment was not meant to be easy. Change is hard and our framers wanted to be sure that the change must be needed and made by more than a majority thereby ensuring that the individual is not steam rolled.
The likelihood of changing for our amendments of limiting campaigns, controlling funding, or getting rid of the electors in the Constitution and 12th amendment are not good, but a few of can dream.