[Keeper of Dol Guldur]

Well, though, Imladris , to be fare, it was Gimli who went on about "faithless is he who turns aside before the task is done", and his decision seemed set in stone, and even after the loss of Gandalf, Galadriel likely was inspiration for him to continue, and of course, his dislike for Legolas evaporated and was replaced by friendship and commaraderie, and Aragorn's staunch, amazing tenacity and kindness won him over ... Aragorn won over everybody ... even Boromir. Aragorn befriended those two so well, they were willing to go to war with him, and like Legolas later mentioned ... if they returned home they'd find war there too, so it wasn't a big deal where in the West they were fighting in the war.

And ALSO, Boromir's death cemented the Three Hunter's resolve, (mainly Aragorn's, but Legolas and Gimli didn't go unaffected), and where would Gimli have gone? He would have turned north and toiled in the Wilderland by himself.

Plus, Gimli, like the other two, was somewhat indebted to rescuing Merry and Pippin, who were captured on his watch, and who were his friends.

So, Gimli didn't even get a chance to act all petty and dwarfish. Dwarvish tendencies showed through all over, pointing out rocks and stonework, smithcraft and that sort, being a little cocky, a little proud, but a generally decent fellow.

I'd say his growth was there. He was just the "Son of Gloin" but he had his own key moments. Balin's Tomb ... Durin's Bane (it affected everyone) ... Galadriel ... Amon Hen ... Eomer ... Helm's Deep ... and Flotsam & Jetsam stand out for me. Also, in Minas Tirith when he and Legolas recount the Paths of the Dead ... they really come across in this great symbiotic friendship ... almost like Merry and Pippin's. Not bad development all in all, for this uncharacteristically heroic dwarf's character.