I am getting a friend into playing WI with me but the core faction decks have gotten stale and we would like to build up something that has more card interplay. I only have the following sets: Core, Ulthuan, and Legends. Since I am a novice deck builder, can anyone suggest an order and destruction deck that utilizes cards only/mostly from these sets? Preferably setups that have good card interplay but aren't too narrowly focused on one theme - which I imagine won't be a problem given the set limitations. Many thanks!

You have those three sets, but have played only with Core cards so far?

If that's the case, simply exchanging some cards in your decks with others from Ulthuan and Legends, or trying High Elf and Dark Elf decks, will spice things up. Also, finding out what works well under which circumstances will probably be more fun than simply following someone's suggestion and copying their deck.