I'm okay with that. I feel like for me, when I see Emma Stone in a role, I see Emma Stone and not whoever she's playing. I want someone who I can look at and just embody the character. And, that's probably going to be a lesser known actress comparatively.
I'm not particularly disappointed that Emma won't be Sue, but...to be fair the exact same criticism could be said of RDJ, Gwyneth, Pratt, and any other number of MCU actors (particularly the rumored Adam Driver, in my opinion...who may be a good actor in terms of emotive ability but I have never found him particularly transformative).
The First Family is going to be some of the trickiest casting they've had yet. And to be honest, I'm not even sure how/why it will pay off. The Four's historical importance can't be understated, but...in terms of what they'll be bringing to the modern MCU I'm not exactly sure (then again, I thought the same for the Guardians).
I admit, I just want to skip right to the X-Men, hahaha. I don't think I have patience for one or two F4-centric phases, I dread wondering what we'll get post-Multiverse Saga...