I have to say, as much as I love All-Star, I am extremely wary of them returning to a Silver Age mindset for Superman in general. I can't help but equate the Silver Age with Reeve/Donner cinematically and I just want Post-Crisis Supes to get his due on the big screen more than anything. Going back to Silver Age feels so regressive to me, so I hope Gunn is only taking inspiration from All-Star in spirit, and not approach/characterization.
Also, I was watching some random George Reeves episodes yesterday, and I still think if you're gonna use Morrison for inspiration, their Golden Age-inspired stuff from N52 Action Comics is MUCH more the way to go. Reeves was just as magical as Reeve in the role to me, and I'm sorry that his work was so long ago that so many generations are missing it. Clark Kent and Lois Lane as rivals with banter is just a joyful dynamic to watch. The resurgence of Golden Age aspects that writers like Morrison and Waid brought back in the Post-Crisis era feels simultaneously true to the original intents behind the character AND very fresh and modern, imo.