Often the choice they make indicates how they want their papacy to be. Leo 13 was there pope most focused on workers' rights:
Pope Leo outlined the rights of workers to a fair wage, safe working conditions, and the formation of trade unions, while affirming the rights to property and free enterprise, opposing both socialism and laissez-faire capitalism.
Franciscus picked a new name as he wanted to be in alignment with Franciscus vows of poverty. Benedictus was more on the strict interpretation of the gospel.
If only there was a way to not have to rely on presumption...