Surely - not 10. Even in a wave. 6? May be, but it will reuire a really BIG wave.
I honestly don't think 6 seats would require all that big of a wave. In a favorable atmosphere, Dems should easily hold all their seats and take Wisconsin, Illinois, and Pennsylvania, plus have a shot at North Carolina, Florida, New Hampshire, and Ohio. Taking all those seats doesn't seem like a huge wave to me. In a huge wave, Iowa, Missouri, Indiana, Georgia, and Arizona could all be in play, plus possibly Kentucky and Alaska.