I like Dragon Rampant, and have been using it since it came out. I like being able to use the upgrades to "personalize" units, like adding Slayer and Fear to represent Jaime Lannister. Also, Lesser Warbeasts for Bolton War Dogs or Spellcasting for Warlocks or Red Priests/Priestesses. Oh, and Flying, Fire Spitting Greater Warbeasts being ridden by petite blonds

. You can easily add bits from Lion Rampant/Pikemens Lament such as Dueling, campaign rules, Banner Bearers/Holy Men (LR Dark Ages rules) and more. Between the 3 books, there are at least 24+ scenarios to play/adjust/tamper with, and you use those in TMWWBK with some tweaking.
The size of games (40-60 models) makes it relatively easy to create new forces for each house or faction. Adding a unit or 2 can easily shake up your army list and give you a painting challenge. Want to add in a unit of Fierce Foot (aka lightly armored, fast moving warriors, slightly uncontrollable but hard hitting) to your prissy Lannister force. Paint up Shagga and some of his boys. Need some allies to fight wights for your Baratheons? Black Watch to the rescue! Or vis-versa! Like the pageantry of all the lesser houses and their coats of arms? Paint up a unit for each lesser house, or mix them together in a unit!
And once you have gathered a big army, Hail Caesar or Sword and Spear (regular or fantasy) or Swordpoint would work a treat...