If your are playing it like role playing your are leveling your character fitting to what you are doing at the time, not with some end battle of the game in mind.
I don't agree with this, and I think lot of others would be in the same boat. While you may not play the game building a character specifically for the last fight of the game...many people do play RPG's with the mindset that "I'm going to make this character the best <insert job/class> I can". They have a general idea in mind about the direction they plan to take the character, with a little wiggle room built in for surprises along the way. I doubt a lot of people would play with a willy-nilly approach of just skilling up in whatever ability is the most relevant at any given moment, because that would leave you with a really random character that was
ok at doing a bunch of different things, but likely not
great at anything.