First, Sam, you need to speak for yourself and not for everyone else. Cite a poll or something, don't just run off and say what everyone thinks. You don't know what the audience is thinking.
Second, you can have Cap feeling out of place. What is boring is having Cap go to the corner store for the sake of going to the corner store. Unless it does something to advance the plot, it shouldn't be included because it's boring. Too many scenes that don't work for the plot really drags on a film. Besides, I don't think there will be enough time to focus on Cap struggling when the film needs to introduce Falcon, VanCamp's character, several baddies and the actual plot. Rehashing something the audience should know is boring.
I'm not saying there won't be something that shows Cap struggling, what I am saying is that it won't be shoved in the audience's face the way I think some of you have suggested. The corner store could work if in the store Widow or Fury or someone shows up and initiates conversation leading into the plot. The corner store or whatever needs to work toward something otherwise it could be cut and the audience wouldn't miss anything.
A corner store scene where he just has an issue can add depth to Cap's character, sure, but I think this is stuff the films (CA:TFA and Avengers) have already touched on and going over it again is just boring. The audience was already shown Cap is confused and wondering where he is at the end of the Cap film. During Avengers, Cap and Fury have the bet for $10 and the flying monkeys reference. We also have the Stephen Hawking/smart guy thing with Coulson. The audience should be aware Cap is out of place by now. Spending more time focusing on just that will be boring and slow the progression on the film.
How many films do you want that focuses on Cap being out of place? Is he always going to be amazed by a microwave or a cellphone or a television? Eventually he will need to get over it.