Retrospectively and With the benefit of hindsight

Retrospectively adverb - In a manner contemplative of past events.

With the benefit of hindsight and retrospectively are semantically related. In some cases you can use "With the benefit of hindsight" instead an adverb "Retrospectively".

Retrospectively and with the benefit of hindsight are semantically related. You can use "Retrospectively" instead an adverb phrase "With the benefit of hindsight".