Xenoblade Chronicles had a ton of stuff you could do like:
adding gems to equipment
customizing party members
finding a unique team to match up against any battle
finding out whether to use Physical or Ether attacks
skill brackets
the whole aggro-agility-defense triangle
and all those heart-to-heart events
yet i was able to work my way through the gaming using just Shulk, Reyn, and Sharla. i changed my equipment every boss or so but that was it. it can be as complex or as simple as you want