As someone who did not like the Heyward-Miller trade, I have to say that it is looking like a clear win for the Braves.
But if my recollection is correct there were many (who liked the trade at the time) who said whatever happened in 2015 was irrelevant in evaluating the trade because the team was too flawed to have a chance in 2015 and that the Miller trade was a good one because we got a player who would be under team control until 2018. Now I don't have a precise recall as to who advanced this argument, but I hope that none of these people would now claim that they were right about the trade based on what has happened so far in 2015.
In general, I would assume that all of those who wanted to punt in 2015 would not feel vindicated because the 2015 team is better, more fun to watch, etc. than expected. I would think those who wanted to punt now in exchange for a presumably much stronger team in 2017 would want to wait and see whether their hopes for 2017 are realized.