Are you sure you're not just using the movie as the basis for Jean's loss of control?
Here's the fact: We don't know if Professor X's fears were valid. If Mastermind had left her alone, it's quite possible that she would have gone on using her powers without any loss of control at all. In fact, we know that this is more than a possibility since, in Morrison's arc and even a little before then, she was exploring her powers to their fullest potential and doing just fine with it. Jean constantly stated, over the course of decades, that she was tired of everyone being scared of her immense powers and trying to hold her back, that keeping her from really cutting loose just made her feel stifled and caged. It's part of the reason she and Scott grew further apart, because he couldn't deal with that. Who's to say that, by putting those blocks in and reigning in Jean's powers all the time, Xavier didn't actually do more harm than good? We don't know. It wouldn't be the first time, though.
Here's another fact: We don't know what would have happened to Rachel, in control of the PF, if someone like Mastermind screwed around with her mind. Who's to say that she wouldn't have experienced the same exact loss of control? Again, we don't know. Jean went through an entirely different experience as the Phoenix than Rachel did, so it's a bit unfounded to be comparing them and saying "This didn't happen to her, so the other one is better." That's all I'm saying.