At this point it's safe to say that Captain Marvel will play an integral part in defeating Thanos. She is suppose to be "the most powerful character" so that will play a big role in how things turn out. I still don't expect or want her to be that much more powerful than some of the existing characters. The best way to have her come in and help save the day would be to use her powers in a smart manner, she doesn't need to or should be the best, strongest, more durable, more powerful, faster, smarter... she should have a particular set of skills that make her excel over other characters but not overshadow them.