What do you fight for?

[Zigûr]

Originally Posted by Tuor in Gondolin

Faramir, while motivation is generally seen as uncorrupted, battling evil, also seems to be afflicted with a bit of elvish regret for passing time and past times. Perhaps motivation includes a similar wish to hold time back.

However, Gandalf seems to suggest younger Denethor (before the loss of his wife) was more idealistic, at least relatively.

Personally I read Faramir as someone accepting of the changing nature of history. While I agree that there might be an element of that regret in his nature, the strength of his conviction is such that he is able to accept the irrationality of that regret and understand the "need of our days."
This is why I find him to be such a powerful foil to Denethor, in that he still understood that the war against Sauron was a moral imperative and not simply one of political manoeuvering. Denethor certainly did, like the Noldor, desire stasis: "I would have things as they were in all the days of my life." By contrast, while Faramir may have found Gondor's deterioration (and the spiritual deterioration of Men in general) to be an unfortunate thing, he accepted it as a fact he could not change. Denethor wished that he could change it and was unable to compromise that desire, hence his despair.
Boromir, by contrast, wished to reject the ingrained traditions and revolutionise Gondor. He wished for the Stewards to be Kings, and for himself to be the hero and saviour of Men. I think Faramir is Tolkien's rejection of both of these extremes, Denethor's fatal conservatism and Boromir's dangerous revolutionary fervour.
This is, of course, simply how I read the characters, but I think Tolkien portrays Faramir to us as the best example of the three.