If you are letting the computer do the work then yea it does get boring.A creative game that's a bore to play.
If a new game were developed solely for Blitzball, then I'm sure it'd be more exciting. Enhanced graphics, more teams/players, and some added extras. I could have fun playing that.
The mini-game on Final Fantasy X? Yawn. Slow and boring.
I did all of the work and ended up hitting level 99 with most of my characters. Also Blitzball was the only reason for me playing ffX; seeing as how the game was epically easy.