you don't seem to understand the distinction between peeling and support. support is offensive as well as defensive, peeling is purely defensive.
rets support was very good before they gutted their healing potential, with its healing no longer as powerful as it once was ret's support loses a lot of value. a ret's heals were literally half their value to their team, you don't bring rets for their burst, thats an added bonus, you bring ret's for their capacity to keep a stronger melee offensive and mobile. the pvppower nerfs also gutted ret's survivability making them even less appealing to teams because they end up being the one who gets trained the whole match because of their weak defensive.
their burst was also not as great as its been in the past, its about equal with enhance's and rets are just as controllable as ever during it. warriors and ferals both burst harder.