I'm not a fan of the elemental affinity. It was designed to weaken its uses in standard rainbows while keeping it stronger in life-based decks (or life-based rainbows). As this is no longer the case, no elemental affinity is really needed.
Secondly, mark-based affinity is really quite a strange way to go about it. It means you could never gain the full 5 HP while getting the most out of Shard of Void, Shard of Divinity or Shard of Bravery, but you CAN with any of the other shards.
Finally, this punishes duos or trios which have arbitrarily been designed to have a certain pendulum/pillar split. This then bleeds into events, and in particular War, where any non-Life element has a much easier time gaining the full 5 HP bonus, but Life itself can't pull the same trick without running a mono (or close enough).
5 HP per turn would indeed be very good, and probably put Life's healing to just below where Light was prior to this change (SoD's change being a large boost to Light's healing too). For an element which supposedly focuses on healing, there isn't usually enough of it at hand due to how specific Empathic Bonds' healing is. And rather than outshining Empathic Bonds, this should complement it by helping stabilise decks until they can fall back on the crazy high healing that only Empathic can provide.