This card alone inspired me to build build a deck around the Noldor trait and to get deeper into deck building for Lord of the Rings in general.
It combines key elements of the Noldor trait in one card, very much like Elven-light.
1) You can only play it from your discard pile.
2) You will be able to play it again and again.
The effect on the deck:
At first glance, a card that can be played only from your discard pile is worse then any that can be played from your hand, because it has to be moved to your discard pile first. However, there are many effects in the game that force you to discard a card as a penalty. Be it strong player cards like Daeron's Runes or Arwen Undómiel or encounter cards like Treacherous Fog. Having cards that can be played from the discard pile lets you turn a penalty to your advantage.
To limit how often you can play Lords of the Eldar it is placed on the bottom of your deck after you played it, otherwise it would just be placed in your discard pile again. This results in an interesting question. Do you want to play it just once like a normal event or will you try and get through your deck quickly to be able to play it over and over again? The answer will influence the deck building by a lot. Even more if you decide you want to play it often.
The effect on the game:
But the card offers so much more once you think about on how to build a deck to get the most out of the card and its advantages. There are cards that are almost always useful and are a staple in almost every deck of the sphere they are in. Lords of the Eldar is different, it is keyed to a trait and thus leads to a more thematic deck or even fellowship of decks. Which can lead to a whole new way to experience known quests or the saga. If we get more cards like this, there will always be something new to explore in The Lord of the Rings, which I consider a good thing.