I have a few concerns about Fallout 4. Some of this will be small. But, I feel it deserves mention.
For the PS4, don't try to do more than the console can handle. You already tried that with the PS3 and failed miserably. You have the specs for a standardized system -- use them.
I don't know about you. But, I want some new enemies. I'm tired of Bandits, Deathclaws, Gangs, General Bad Guy, Robots, variants of BoS, Raiders, blowflies, radscorpions, rats, ghouls, mutants, etc. I want them to stretch their creative juices. I want them to show me something new. We are going to a new region. I'm sure there would be different mutated creatures. How about mutated bears or mountain lions? So far, the trailer has shown me they know how to recycle previous game elements (including the Bobblehead in the gas station). That doesn't actually bode well. It means the enemies could act the same what they did in Fallout 3 and New Vegas with eratic movements -- apparent lightening reflexes and such. For the love of god, redesign Power Armor so that it actually looks cool.
I'll grant them a new story is a great idea. I'll even admit I enjoy the games. But, don't expect me to purchase day one if it's all the same stuff. I have Fallout 3 which means I can run around with a dog if I want. I have New Vegas which means I can kill the same enemies all day long ---. Last but not least, Bring back the deathclaw gauntlet.