Oh absolutely. Honestly it would probably be more effective to implement voting reform (single transferrable vote FTW) if you're going to the bother of a constitutional amendment.

As for your link, I can't even figure out what their proposed text is.

They actually used to have the text of an amendment. Now their website is more flashy but with less content. Too bad. It's about non-personhood of corporations and restrictions of corporate donation at the minimum, and at the maximum something like publicly-funded elections.