The problem with Aragorn in the films is that he is... An important protagonist.
And Storytelling 101 tells us that an important protagonist needs to have a character arc.
The thing is, Aragorn doesn't have a character arc in the LOTR books. His character is largely static. His entire arc was in the backstory, prior to the events of the books. By the time the book starts, he knows exactly what he wants, he knows exactly what he's willing to do to get it, and he does it.
The film, in order to give him an arc, muddied those waters. He turns from being a noble, confident, driven man, into a wishy-washy one-foot-in-one-foot-out wandering stoner, who spends most of his time moping, and the rest with no idea of what he wants, or what he should do to get it.
It makes for character development, but it is not an accurate portrayal of his book character. Much of his nobility in the books comes from him not having these kinds of hangups - he knows what the right thing to do is, and he does it, and people around him are awed by his conviction and charisma.
I usually don't like 'great man' stories, but I have a soft spot for his part in the LOTR books.