I think the 5 to 1 debate should also include Panthers because in many ways they were superior machines. I also think what often gets overlooked in these debates is how the combat vehicles were optimized for the roles that they were expected to fulfill. The heavy German tanks were developed as answers to the t34 in this regard they were successes. However then a question must be asked. Could these vehicles have fulfilled the t-34s or m4s role as the armor component of a sustained advance? I don't believe they could. They were too unreliable too complicated and not optimized enough for mass production in my opinion. I think the 5 to 1 ratio debate is just too simplistic to give an accurate understanding of the relative merits of the combat systems involved, but it does give us a good starting point to get deeper into tank evolution during ww2.