That wasn't my question though (I think I may have misleaded you, my bad) I agree that his storylines were almost gone, that's why I agree that he went downhill after he left. My question was what do someone's personal achievemnts (in the character's life itself, not the story of it) have to do with his developement? I will repeat my example: there could be a character of a loser, and he keeps being a loser, and never gets a girlfriend, never gets friends or a job, but he could have many storylines that will develop his character, even if he doesn't make it well in life. He could still progress, either for better or worse. That's a character development, not what the character itself does in life, it's about the changes that happen to them. My question had nothing to do with Giles (although it did seem like it from my phrasing, sorry). Yes, he didn't have many things in life, and yes his storyliines became unimportant and pretty much unvisible. But that doesn't have anything to do with his character development. He could still have the same things and do the same things and even have no serious storyline, but inside him he will change. His life hasn't changed much, but he did.
But again, I was asking in general about your character development take, which as you said before, you didn't exactly understand what character development was.