Erkenbrand has very quickly become my go to defender. His ability is so strong compared to other shadow cancellation options - it's available from turn one, it doesn't take up a restricted slot, doesn't cost resources, and it's can be used on every shadow card for every attack he defends. Having Sentinel also helps protect other players before their shadow cancellation is found ready to go. The only restrictions are that he needs to be the defender and the number of hit points he has available.
The release of Ancestral Armor and Hauberk of Mail has improved his capability significantly - they increase both defence and hit points which is exactly what Erkenbrand needs. If he has both he sits at 6 and 7 , and still has an additional restricted slot for an Armored Destrier to make sure he can use those stats to their fullest.
Any readying he gets can always be put to good effect - taking multiple defences, his 2 can be important in the early game, and in desperate times he can commit to the quest for 1 as well.
Including healing with him is important, but that isn't the restriction for deck building that it may have been - Magic Ring is another strong attachment that can provide healing or readying at the cost of threat, if including Lore isn't what you want to do. Dúnedain Remedy can also work when in combination with Rune-master or The Day's Rising (which are all in sphere), but takes a bit more to set up.
Including Lore is the easiest way to get the required healing, but I've found I include Lore anyway to provide the card draw to find Ancestral Armor and/or Hauberk of Mail sooner rather than later.
Even if you consider healing as requisite to using his ability to ensure it can be used repeatedly, the cancellation is still available before the healing turns up and the damage can then be healed later. Finding the healing is no different to finding A Burning Brand or Staff of Lebethron, but being able to use the ability while still searching for the combo piece is significant.
It's a fantastic ability, and I've found myself longing for it in decks that don't include him. The early shadow that causes an additional attack, or the attack to be undefended, or to discard the attachment just played can really hurt, and Erkenbrand makes sure that doesn't happen.