Well it does. Because we are left out of the loop why Anakin changed so much between TPM and AOTC. He is just 'suddenly' different.
Plus, Anakin doesn't do much in TPM. He's primarily passive. Everything relevant to the story that he 'did', happened by accident. So there was no purpose/reason/motivation behind his relevant actions (which is basically blowing up the droid control ship - he never intended to go into space, he never intended to crash in the ship and he never intended to blow up the generator).
If a protagonist has no motivations, and no actions to achieve his 'object of desire', there's not much of a protagonist. Definitely not in an adventure movie like this.
In AOTC we see that Anakin does want something. It's rather vague, but at least he wants something. He's still quite passive though in achieving his goals (he does all kinds of other stuff, but generally he gets sent off on some kind of errand by others).
And does Vader 'deserve' what happens in the OT? I dunno. Nobody deserves forgiveness. It is a gift given by others. We do see Vader trying to redeem himself. Before the PT the last scene in ROTJ always struck me as Vader regretting everything he has done. that he couldn't break free alone, that he NEEDED Luke to show him the way. But that he also knew it was never enough to undo what he had done, yet having his son look at him with a great caring, DESPITE of what he had done, was enough redemption for him.
The PT kinda made Anakin a cosmic superhero that was instantly given Force afterlife... To say someone deserved what he got by means of the details to his backstory that was invented much later, is a very hard question for me to answer.
I cannot answer such questions without taking the history the filmmaking itself into account. And from that POV the PT is quite the mystery: why did it turn out this way?