The ring that Anet compared has a 4% stat bonus (48 --> 50) and that is just one piece.
My maths can go a little wobbly when percentages are involved but if each items carries a 4% bonus in stats over Exotics and there are 6 armour, 6 accessory and 1 (or 2 but 1h tend to have half the points of 2h) weapon slot then that is a 13*4= 52% stat bonus over exotics (full sets of each)
Again maths can be off with percentages so feel free to correct me
Errr... Wouldn't the diff still be 4%? You don't multiply percentages just like that...