I would have happily had a lot more Imrahil ... but I have always felt that he and Faramir are cut from similar cloth - and there is evidence to support this (though inconveniently mainly not in this chapter) for a start Faramir and Imrahil both have an "elvish" quality
I still think that it is harsh of davem to paint Faramir as, for want of a better word, a snob for his regret that the men of Gondor have declined. One can seek equality at a high level rather than that everyone be reduced to the lowest common denominator. If you think of the descriptions of the various troops of the lords of Gondor, those of Gondor are portrayed as the "noblest" - but this includes the men at arms rather than just the knights and the prince. Yet I do not assume that necessarily that a plain soldier of Belfalas would rank higher than a lord of Lamedon say.
Belfalas seems to be a microcosm of greater Gondor as it might have been. It maybe wrong to include reference to HoME, but one of the problems of Gondor was the failure of the kings to ensure the succession. At the time prior to the War of the Ring, even the house of the stewards is on shaky ground. Boromir, for all his desire to know how long it would take to turn a Steward in to a king, has shown no inclination to do his duty on the posterity front
. Meanwhile from the HoME genealogies, the line of Dol Amroth has passed on in seemingly unbroken succession, and Imrahil has four children and a grandson. Furthermore, the Princes of Dol Amroth have never made a claim on the crown of Gondor, Imrahil has the wisdom to follow the guidance of Gandalf rather than assert his own authority and he recognises Aragorn almost instinctively and without rancour - just as Faramir will do. Belfalas, by the sea, is literally and metaphorically closest to lost Numenore and the west. And this noble gondorian line resulting from the union of a numenorean and an elf is an encouraging precedent for the union of a dunedain and a much nobler elf woman at the end of the book.
Imrahil fills the void left by Denethor in his nephew's life. It is he who rescues Faramir and bears him back to Denethor with the reproach "
Your son, has returned after great deeds". He is proactive while Denethor is passive/negative. It is fitting that Faramir will become prince of Ithilien ( which is in different ways a mini Numenore)
to paralel Imrahil's own principality and marriages between him and Eowyn and Eomer and Lothiriel further reinforces the ties - it is virtually siblings marrying siblings.
Oh dear I fear this should be elsewhere ... but Imrahil is second only to Faramir in my book and so I risk turning in to the bunny boiler of Middle Earth
(but that was Sam, last chapter wasn't it) :P