You can actually beat the game with only 3 characters. Almost the entirety of the World of Ruin is optional. Granted that's difficult to do, but it's a nice challenge. If you want to actually get all the party members and get all the espers and good equipment, you still have a good ways to go.

I've beaten all except IX, X, XII. I plan on getting through IX after I finish XIII-2. I never got far in IX, but I enjoyed what I played. Then XII, which I got far, but then got distracted with school and forgot where I was/what I was doing. I honestly just hate X and have no desire to beat it. Though I do want to try X-2 purely for that battle system everyone says is so good.

THE JACKEL