I'm going to vote for switch, especially since it could be a massive popularity boost if its a launch title as well. (kickstarter.com)
The Year undoubtedly resulted in a huge popularity boost for the green and previously understated bro with special communities opening up on Miiverse, key Nintendo staff changing their Miiverse profiles to be blue and green, as well as a surge of Luigi usernames and communities across social media. (superluigibros.com)
They DO favor titles with high ranking in their category and BECAUSE KU pages read are INCLUDED as a factor in the rankings, KU popularity BOOSTS a titles popularity / visibility, which raises KDP Select titles over equally good non-select titles. (writtenwordmedia.com)