Irvine was always one of my major-junctioned teammates for the final battle. He has a badass gun(ok, so not as badass as Laguna's but still it's badass) and he has his own style. The assassination part might be a failing point for him, but he retributes by saving the whole party from prison. He has some nice lines and his limit break is wicked.

One of Irvine's fine lines:
"My turn to boogie."

Also, how many cowboys do you see in FF?
Answer: ONE.