I tried to identify a real issue: the GOP creates a problem for itself when it splits the ticket with two Republicans who have fundamental disagreements.
You make a powerful and cogent argument against this observation, and yet I continue to think it is a problem.
How many "pure" tickets, or cohesive tickets, can you recall, especially on the GOP side? Reagan had Bush (much different than himself). Ford had tried to offer Reagan the VP slot. Kemp was a supply side pro-lifer who went with the RINO Dole. Even going back to FDR, Truman was brought aboard in 1944 specifically because he bucked up FDR's anticommunist creds.
So I don't think this is a fair criticism. It's politics, and has been for a century.