Iambic pentameter in "Love Among the Ruins" has a really piercing effect on the poem, in that, the longer line reads smoothly, then the shorter, three syllable line emphasizes meaning, in a singular way. (It almost sounds like a song; as readers, we wait for the "refrain" similar to waiting for the chorus in a song.) The effect is we remember the short syllable lines more intensely.
In "Love Among the Ruins” he describes in detail, a city that has become a place void of relgion and meaning due to war, of course. However it is romanticized, “they built their gods a brazen pillar high / As the sky” (7.75). Robert Browning is a master of using iambic pentameter. In this poem he uses differing voices to convey a totally different meaning.
He doesn't interpret the fall of the city as occuring only due to the war. It is money. He says “And that glory and that shame alike, the gold/ Bought and sold” (3.35-36). He comments on capitalism that changed the culture and even the language that was used in Victorian poetry.