X wasn't completely linear.
Yes it was and I do not think that is a bad thing. I've seen dozens of games that are free-roam and open world to have incredibly bad and disjointed stories without any well-developed characters.
Lots to explore
No there wasn't. Both had a set path that opened up towards the end. Both had end game activities to extend the life of the game well beyond 100 hours. XIII didn't have anything near as fun as Blitzball, but I don't see an argument past that.
Between being duped by SE on XIII and the online thing,
How did they dupe you? There was a ton of media on both and you could well beforehand what the game was going to be like. This goes for both games.