Rebellous Obi-Wan Kenobi?

Allow me my little Qui-Gon moment: "I'm not sure."

In earlier drafts, before Lucas brought Qui-Gon forward into the narrative (he is originally introduced when the heroes arrive on Coruscant), Obi-Wan has most of Qui-Gon's traits -- and at a younger age than Qui-Gon himself. Obi-Wan serves as the audience guide. He alone is sent to negotiate with the Trade Federation and narrowly escapes, rescues Jar Jar from punishment, shepherds the Queen and her entourage off Naboo, and critically, once they've fled: he is the one who finds Anakin on Tatooine, brings him to Coruscant, and argues his case before the Jedi Council; which, of course, are all the things that Qui-Gon does in the final film.

I guess Lucas thought this setup and structure wasn't as interesting as placing Obi-Wan more in Qui-Gon's shadow and having the Jedi work together in Master-Padawan pairs, which also created a stronger resonance with the Sith ("Always two there are"). Interestingly, the young Sith apprentice kills the older Jedi Master, while the young Jedi learner kills the Sith apprentice. So, in the case of the Sith, it's the Master who lives on; and in the case of the Jedi, it's the Master who is eliminated.  

That little inversion in itself suggests that Lucas was basically saying, "The Jedi are fucked now." Without a major lodestar like Qui-Gon, a critical piece of the beating heart of the Jedi is stripped out, placing Obi-Wan in a difficult position. Obi-Wan loses his main mentor and putative father figure: a pain he shares with Anakin. But he also takes on Qui-Gon's mantle and becomes Anakin's mentor -- at a younger age, when he is less experienced and essentially still grieving the loss of Qui-Gon (that Jedi doctrine tells him he can't do). This obviously has consequences for the two of them going forward. At its core, this fallout from the events of Episode I is the story of the Prequel Trilogy, the main device that introduces dramatically-necessary psychological tension (which Palpatine exploits), and it's hard to imagine it another way.


He also stresses it in "The Making Of The Phantom Menace", by Laurent Bouzereau and Jody Duncan (p. 8):


I think the idea here is that helplessly seeing Maul cut down his Jedi Master puts a little fire in Obi's belly. In a precarious moment against Maul, when the situation seems hopeless, Obi-Wan literally rises up and defeats Maul with his Master's saber -- a stirring affirmation that Obi-Wan has what it takes to shed his conservative skin and become (more like) Qui-Gon (in the wider span of the story):

 






Notice, as well, before Obi-Wan rises from the pit, the Droid Control Ship is destroyed, leading to freedom on Naboo:





All the machine forms are destroyed -- just like Obi-Wan defeats his machinic adherence to Jedi doctrine and starts putting his faith in the Force, enabling him to defeat Maul and share one final precious moment with his fallen Master.

In the following prequels, we also see that Obi-Wan has a bit of Maul in him, when he enjoys a burst of fiery destruction (much as the fiery explosion of the Droid Control Ship seems to liberate his will-to-survive tiger instinct):



"Good call, my young Padawan!"



In AOTC, in fact, Obi-Wan really gets into the fire motif, even using expressions like "Blast! and "What in the blazes?!"

In ROTS, Obi-Wan maintains his love and trust of fire being a liberating energy:



"So uncivilized."



Alas, this love of destruction is revisited on Obi-Wan in a tragic way at the apex of the story:





It's like Obi-Wan is a more condemning, less honed version of Qui-Gon or something.

Despite Lucas saying that Obi-Wan "has become" Qui-Gon at the end of TPM, there are flashes of his deference for the Jedi Council and the Jedi Way of doing things, even here. Such as when he tells Anakin, "The Council have granted me permission to train you." Or the wary, concerned looks he flashes in the final scenes:






Yes, that could have been a good direction to take the story. However, I think Lucas decided that Obi-Wan should double down on his conservative persona, in some ways, because of how rebellious Anakin is, in kind. That said, we do see instances of Obi-Wan displaying edgier behaviour (as you've stated), and even clear evidence of the pair getting on better at the start of Episode III.

When their relationship begins to crumble after the Jedi Council decree that Anakin must report on Palpatine's dealings, Obi-Wan tells Anakin that he is on his side and that he didn't want to place him in the situation. In the next scene, he defends Anakin to Mace and Yoda, and even offers a rosy view of their relationship: "He will not let me down. He never has." His desperation on Mustafar to still reach Anakin and find a way out of the mess is palpable. 

Even Obi-Wan's little dabs of reassurance to Anakin in Episode II are reminiscent of Alec Guinness' Obi-Wan (whom Ewan was always conscious of respecting/emulating). When he mirthfully tells Anakin in the elevator that he's sweating and he should relax, it evokes Alec's Obi-Wan warmly telling Luke after he revives him in the Jundland Wastes, "Rest easy, son. You've had a busy day."

Perhaps Obi-Wan was more rebellious in Lucas' earlier conception of TPM. After all, it would fit better with Obi-Wan countering Yoda's reluctance to train Luke because of his recklessness: "Was I any different when you trained me?" I think Lucas ultimately decided to try and split the difference. In their very first scene together, Obi-Wan defends his uneasy feeling by telling Qui-Gon that Yoda taught him he should be "mindful of the future". Later on, Qui-Gon calls Obi-Wan "headstrong" in front of the Jedi Council. Perhaps Yoda detected that Obi-Wan was a little too "in the moment" for his tastes (i.e., a promising Padawan who could nonetheless be impatient), and calling Obi-Wan headstrong is Qui-Gon's version of that. Thus, there is a little bit of rebelliousness in Obi-Wan toward both sets of Masters and their philosophical imperatives from the start -- but maybe it's sometimes a little hard to notice, because Qui-Gon and his role in the story cast a long shadow. A shadow that even Obi-Wan could never fully escape.

I agree with Alex. However, rebellious is a tricky term. There are at least two meanings behind it: rebellious in general and rebellious in certain circumstances.
If it is possible to define Obi Wan with some kind of rebelliousness, while it is very...volatile, it should be the second type.
Obi Wan is indeed headstrong, at least in the beginning of his training, but he is such as he is convinced that following the rules strictly can be the only way to not deviate from a right path. As I wrote in another thread naberriefields.freeforums.net/thread/129/cowboy-farmboy-nerd-mentor, Obi Wan changes a lot during his life, achieving the wisdom Qui Gon had but he did it graduately, and succeeded with Luke in it. In the beginning, Obi Wan was put in interesting situation: he was stick to the rules but his master wasn't. In a way, he was rebellious but only because his master was defiant to many Council decisions, so to follow the rule, Obi Wan had to be rebellious regarding to Qui Gon and respectively obedient to the Council. In a way the roles were reversed when he trained Anakin

The reasons that there were some frictions between Obi Wan and Anakin and not so much (with one exception) between Obi Wan and Qui Gon is because Qui Gon let Obi Wan be, biding his time, seeing the things by himself. Patience of the master is the key, yet Obi Wan didn't have with Anakin for the same reason: he wasn't ready at this point. Yet Qui Gon was, so their master-apprentice relationship worked. Is not that that of Anakin and Obi Wan didn't work, but there was some tension, especially in the beginning paradoxically for the same reasons that Obi Wan would have tensions with Qui Gon if Qui Gon had another atittude: Obi Wan wanted to follow the rule and Anakin wanted to achieve the purpose.

So to answer the question of Samnz: I have no idea if Lucas intended to show more rebellious Obi Wan in the beginning, but I like the final result as it fits more to the story.

The funny thing about Obi-Wan is he goes by the book until push comes to shove. Until it's time for him to act in the moment on instinct. Like when he insisted that he and Anakin only protect Senator Amidala but not investigate. Then when an assassin droid was right there at the Senator's window, and a brief window of a chance to investigate presented itself, he jumped.