Tidus.
If I had to pick a character who was the most bland and uninteresting in the main FF game, it would probably be Lightning. She had character, but the subtle sort, and it definitely didn't show up well against such unsubtle nimrods as Snow. XIII-2 wasn't much better: her voice over narration makes sense in retrospect, but it's still kinda bland.
But then her character in Duodecim was amazing, and she contrasted Kain, Vaan, and Laguna perfectly. She's not exactly a bad character, but the characters she was surrounded by didn't complement her properly.
Tidus on the other hand, was outright terrible in everything.







