I try to watch the numbers of the set we can possibly use on the teams. Ok, numbers below.
But why do we need them so many? we play only with few of them on PvP and PvE content
S2
mythic helmets 9 sets
mythic chests 11 sets
legendary helmets/chests 15 sets
= 35 sets
VS
S3 preview in box storage
mythics 20 sets
legendary 14 sets
=34 sets
As summary of those numbers in s3 percentage% should be better but only on finding legend item sets. We gonna struggle with finding good mythic and lot harder to find good gear mythic+