Erestor opens up new possibilities with cards like these. A particular scenario just occurred to me:
I run Erestor and have 10 cards in the planning phase of round 1. Two of these are Protector of Lorien. The card is not unique and has no "1-per-character" restriction. All it has is a "Limit 3 times" for the discard. So nothing stops me from attaching both copies to e.g. Erestor, discard 6 cards and quest with him for 8 Willpower?
The same could be asked about Elven Spear, as you can have 2 restricted attachments. Discard 6 cards, give e.g. Elladan 9 Attack?
The "Limit 3 times per phase" seems to refer to the attachment in question and not to raising the hero's stats overall. Am I wrong?