Here are the four things heroes need.
The hero must change throughout the story. They must learn something, overcome their fears, become a better person, or something like that. Without this development, the story feels meaningless.
We need to be able to root for the hero. There are two main ways to accomplish this: make them virtuous, or make them mistreated or unfortunate - we either admire the hero or sympathize with them. Usually you want to do some of both.
The hero must be the hero of their own story. Their choices should steer the plot. If they don't, why is the story written from their perspective, instead of someone who actually matters? This doesn't mean the hero should always be successful; on the contrary, good stories generally involve a lot of failure. But the direction of the plot - especially the ending - should still be a result of the hero's actions.
A person old enough to be a POV character didn't just get born. They have a past. What is it? Of course this is less relevant with child protagonists, but especially with adult protagonists you need to explain how they got where they are in life now. This is arguably the least important area, but an interesting past can go a long way in explaining someone's personality, providing plot material, and making them more relatable.
Luke starts out as a farmhand aspiring to go join the rebellion and fight the evil empire and ends up as an experienced Jedi who has faced his destiny. On the outside, the development is severe, but what has he gained as a person? Maturity and confidence, I'd say, except that he wasn't really shown lacking those things early in the story. He never once displayed feelings of insecurity, fear of battle, or difficulty dealing with the sacrifices that come with war, such as the death of his mentor. This failure to show his need for development in the first place makes us feel that he didn't actually learn much. I give him a 2.
Well, he's risking his life in a fight against tyranny, so it's pretty hard to deny that he's the goodguy here. And he never really does anything despicable. On the other hand, the main virtue he exhibits is courage, but the fear that the heroes of Star Wars would be facing in the situations they're in is never mentioned or acted on by anyone, which makes the courage that he exhibits seem less admirable. Still, I'll give him a 4.
Let's see. In the beginning, he chooses to go out and look for R2, but that wasn't much. He didn't exactly choose to go with Ben to Alderaan; his family was dead and his home destroyed so he had basically no other options. Landing in the Death Star was not his decision, although going to rescue Leia was. Nothing about the Death Star battle was his decision. Going to Dagobah sort of was, but not really. Going to Cloud City was definitely his choice, but that was basically his only moment of agency in the entire movie. In the final movie he has much more of it; the plan to rescue Han was implied to be his, he went back to Dagobah freely, and chose to go confront Vader a second time. Overall, I give him a 3 on agency throughout all three movies.
None. 2 points inatead of 0 because he's a borderline child character - he's just been living at home with his foster parents the whole time, so he has an excuse for not having much of a past.
Anakin does pretty good on this. He has a strong inner conflict that is consistent throughout both the movies he's the protagonist of: he is torn between his vow of celibacy and his love for Padme. Revealed in the beginning, resolved in the end - that's the way it's supposed to be. It still could have been fleshed out more, but overall it was decent. 4 on this.
Like Luke, he's a brave Jedi fighting for the republic. Nevertheless, the politics of the war are mostly hidden from us, so it's harder to tell which side is which than it should be. It really hurt his rootability when he complained about not getting the rank of master. Getting put on the council should have been more than enough for him. In his defense, he's in a bit of a sympathizable position what with being ordered by the Jedi council to spy on his friend and then when he makes the decision to report Palpatine to Mace Windu he is told to sit the confrontation out - an insulting breach of trust that makes us able to see Anakin as the goodguy for a little bit longer even after he turns to the dark side. I'm going to end up giving him a 3.
In Attack of the Clones Anakin chooses to go save his mother, but other than that, he makes basically no decisions of his own. In the next movie, he chooses to kill Dooku and then reports Palpatine to Mace Windu though, and that affects the plot plenty. So do his decisions to go stop Mace Windu and then to turn to the dark side. That's much better. I'll give him a 4 on this.
We know a good bit about his past from The Phantom Menace. We also know he spent the interim training to be a Jedi. Unfortunately, we don't really know what training to be a Jedi entails. I'll give him a 4.
Her abusive brother Reen has taught her that altruism doesn't exist and life is just about exploiting other people as necessary to survive. Her arc is about overcoming this attitude, which she does in the end of the book. Revealed in the beginning, resolved in the end - beautiful. 6 points!
Well, the enemy is a government whose cruelty is blatantly visible to the reader, so she doesn't really need to be a great person to be rootable. 5 points.
Not great during the main portion of the book; it's even explicitly mentioned by other characters how little control she has over things. Nevertheless she has a couple moments: making Kelsier let her come with him to Kredik Shaw (which was an awesome scene by the way), convincing Kelsier not to throw away his life when the army gets destroyed (and coming with him on that trip in the first place), and spending time with Elend despite being told not to. Then she becomes fully autonomous after Kelsier dies. 3 points.
We know she's lived as a member of various thieving crews her whole life, barely surviving, and we know what happened with Reen and all. For a child character, it's as deep past as we could have asked for - 6 points.
Kaim knows he is immortal and has lost his memories. He starts out having no purpose and nothing in the world that he cares about, and frequently agonizes over this in his Dreams. His arc is about finding something to care about. It's a beautiful theme for a story, especially given its significance to Protagonism, and not one that is overdone. 6 points.
Not great. He's extremely brave, but kind of an asshole - he chokes Jansen just for following him and never apologizes for it. Nevertheless, later in the story he demonstrates that he does care about people besides himself - he surrenders to Kakanas in Numara to avoid triggering a war, and sacrifices himself to save his grandchildren in the snowstorm. 3 points.
Plenty. He chooses to fight Kakanas at Grand Staff, chooses to even go on the whole quest to take down Gongora, and most importantly, chooses to destroy the mirrors. 5 points.
Excellent. We know tons about him from his Dreams. 6 points.
In the beginning he is a selfish coward. Throughout the story, he primarily learns courage, but also learns to see things from others' perspectives a little better. For example, when he first finds out what Katherine did to David to make him overcome his phobia, he is furious with her, but later in the story he comes to understand that she really did mean well, even if he doesn't agree with that particular action, and learns to respect her for being a good person in her own way. Both are very believable because he learns from the examples of those around him. 5 points.
He's a jerk in the beginning, but soon gets better. And he's being compared to an enemy about as evil as Mistborn's enemy (not Rashek, but the Final Empire in general). He also has become quite brave by the ending, balancing out the teams to his own disadvantage during the penultimate battle and volunteering for the role where he collapses the ceiling. 4 points.
Decent. He chooses to sneak out against curfew, he chooses to go on Leuis's mission, he comes up with the plan to crush a Voren to death. 3 points.
This is the only area where he really bombs. He has essentially no history. I'll give him 3 instead of Luke's 2, because he's younger and so his excuse of being a child character is stronger.
I'll now analyze some protagonists of popular stories and give them ratings in each area. The scale is 0-6.
Luke scores an average of 2.75 over the six areas. Not good, but acceptable.
(He wasn't the protagonist of the first movie he was in, so I'll only consider the second two.)
Anakin scores an average of 3.75 - much better than Luke. That's more than halfway up the scale, making it a decent score.
(I'd love to put Rey on here, but I feel I don't remember enough of what happens in The Force Awakens to be qualified to judge her.)
(I'd also like to have Frodo and Harry Potter, but can't for the same reason)
Now some less popular stories that I've seen.
Vin (from Mistborn: The Final Empire)
(I'll only consider the first book of the series, because it was the only good one.)
Vin's overall score: 5.0 - an excellent score.
Kaim Argonar (from Lost Odyssey)
Kaim's overall score: 5.0. Another excellent score.
And now some of my stories.
Jaydin (from Pillars Of Life)
Overall rating: 3.75.