While I appreciate your thoughts on this, I feel like the original question here is a bit ambiguous - gameplay is different at different levels, that is known. Tier X battles will play exponentially different than a Tier IV battle. As far as your statement regarding 'balance' vs 'new products' -- the teams that perform these roles are different, so adding new products does not detract from balancing, or QAing products.
My question to you, @WM1957 is what do you define as 'best gameplay'. That will help with directing you towards the tier that would match your playstyle.