BT needs stacks to more efficient than IE, BT without stacks isn't that great of an item. Some AD carries choose to go BT first because they have low range and feel they need a decent amount of lifesteal to survive the fight (graves vayne sivir etc.), going IE on them I think is fine but it's up to you. Doublelift goes the BT route on those champions, a large portion of other ad carry players go IE.
Wriggles PD build is meant for high mobility, jungle invasion and early-mid game dominance. A champion like kogmaw will still do a lot of damage.