I don't think it will draw a non cosplay crowd. I think the idea was to make people feel safer but I do not think that "no masks or blasters" will really do this.
I am wondering if the draw of Star Wars is sufficient to blot out the losses AMC may face from those that are not attending AMC showings for cosplay reasons. I would hazard a guess that the same draw from Star Wars fans would be enough to blot out the loss from people not attending for safety reasons too though.
I guess AMC disagrees though since they implemented the rule. Either they don't care about a loss they think will be small, or value perceived safety over the possible loss, or think the safety crowd is larger than the cosplay crowd.