A constitutional amendment that increases the Senate representation of only some states would require the unanimous consent of every state legislature, so it's obviously not gonna happen since that would mean smaller states voting to ratify an amendment that would decrease the relative political power of their state. I'd love to see all of the states be given 3 senators, though, so that every state would hold a Senate election every 2 years, which might - just might - make the Senate a bit more reflective of the current national mood. And it would only require the ratification of 3/4ths of the states to boot.
Glad to see someone shares this idea! I think that it would go well with an expansion of the House, so the overall electoral college balance between large and small states isn’t too different from today so as to get support from smaller states.