I regularly take a journey from Heathrow to Brazil that does not have a direct route, I have to make at least one stop in Sao Paulo. I really do not want to take a flight with more than one stop as that can increase the journey time by many hours.
What would make my life easier is to specify in my search that I want not more than one stop. It adds one more step to the process to get the search result and then start applying filters.
Similarly I would like to exclude flights going via the USA. Only a masochist would ever use an American airport as a hub for an international flight between two other countries; you have a very good chance of missing your connection because of the US bureaucracy.