It is true that Gimli and Legolas have a lot more depth in the books, whereas in the films if anything they regress to comedy dwarf and Elf sidekick. But their friendship has its touching moments onscreen nonetheless, and it simply wouldn't have been possible for any adaptation - with Jackson at the helm or otherwise - to develop every character as fully as they are developed in the novels. Something had to give. As it stands, I think Jackson made the prudent choice.