enough electoral votes to stop anyone from getting the presidency.

Ummmm...what?

But then at the same time something like the presidency should get more than half of the total votes to win.

That would only reinforce the two-party issue you are trying to get away from. This whole idea that past the goal post is wrong is fundamentally broken ideology that says that if a candidate gets _% then you take 100% of votes cast, subtract that number and the remaining amount are against the person who won...but that doesn't take into consideration people's second or third choices in an open competition with more than two parties.

If you want more than two parties, you'll have to give up the idea that a candidate needs over 50% rather than be in the lead, because when votes are broken up among multiple parties, it is less likely for anyone to get 50% of votes.

Here, this video should be of assistance to help clarify why this idea leads back to a two-party system.