Well "small" is relative, as I think she was still in the film quite a bit (haven't seen Gulliver's either, just going by what I've heard), just didn't have much to do, so it was more than just the odd week or two of filming. And yeah, you'd think Marvel would have been able to work around it, but I guess with all the pre-production/training involved with the role, a schedule adjustment at that point would have cost too much time/money for someone who's not even their 1st or 2nd lead. As I recall, Emily herself said in an interview that SHE was the one who ultimately pulled out just because of the headache and back-and-forth of the parties involved, so who knows, maybe Marvel WAS trying to shuffle things around and it just wasn't working.
This is the first argument I've seen against Emily that I feel might actually have some merit. She's my top pick still because she checks all the priority boxes for me (acting ability, charisma, commanding presence, physicality, recognizability/bankability), but I too have noticed the aloof nature of most of her characters in the past. That's why it was so easy to imagine her as Widow. The only reason I can see past it for this is because of her persona in real-life. She seems very fun and a lot more relatable in real-life than her characters have been, so based on that, I feel like she could play that type of role if she was ever given one to do.
