If it's going to be just a Director's Cut, I think we won't be getting a whole new movie. Taking out the mental blocks wouldn't work, I think, because it would mean there is no reason for the Phoenix at all.
What I'd like to see:
An Xavier opening monologue. There is one among the deleted scenes on the DVD, but I'd like to see it with better effects, and music added.
Extended Danger Room scene. We've seen pictures and trailer footage of this scene that isn't in the movie, so they can use that.
Make the scene have more of a "story". Put in an objective for the team. In the novel, they have to reach a certain place before a certain time, while they dodge laserfire. Also, make it a better (re)introduction for this new X Men team: give the characters some dialogue, and have them work together more.
Actually show Phoenix rising from the water. If there is one thing fans wanted to see...and of course, she should have a fiery aura. She doesn't need it in all of the scenes, but I'd say its needed in this one, in the scene in which she kills the professor and when she goes berserk at the final battle.
Add in as much there was of Angel's part.
Show him arriving at the masnion, and join the battle however short that may be.
Extend the battle at Jean's house.
Add in the shots of Wolverine and Juggernaut on the street (but without Juggernaut's badly delivered line), and add in Storm's lightning punches (but without her and Wolverine fying Juggernaut).
I'd personally like to hear the voice in the psychic battle. Some of the lines in the deleted scene we know from the DVD could be used.
I'm not sure if this was filmed, but I'd like to see some reaction to the battle from the people on the street or in their houses. You can see them running away behind Storm and Wolverine, but that's all there is shown, even though it doesn't happen everyday your neighbour's house takes off into the air!
Though I haven't seen the scene itself, adding the scene of the plastic weapons being manyfactured might show the government arming up and getting ready for war very well, and could fit into the montage of the army taking those weapons into use.
Put back in the original version of the X Men boarding the jet. Wolverine is not the guy for speeches, and the dialogue in this scene seems a bit more dramatic, it shows more what is at stake.
Add the scene of Jean sensing a scared girl. It would add a little more conflict to Jean.
In the final battle, add in Storm's wave, and Bobby and Colossus' teamwork in defeating Phat. We hardly see Storm and Colossus do anything during the final battle.
Add in the extended Dark Phoenix destruction. Not only does it look gorgeous, but it also shows more of her power.
Put in the alternative endings of Rogue not being cured, and the new schoolyear.
Thanks! 
