How many people should be Head of State

Have a look at this dilemma. I feel there is no right answer: all of the positions have massive openings for abuse... The "one-leader" option seems to be the most practical, but really, can one person have the final word in all those decisions and still know what the hell they are doing?

Depends on the specific situation. For example (off the top of my head), a developing nation that needs to catch up fast may want a single/few leader system because it is more efficient. But of course, who that 'one' leader is can matter a lot and often it just comes down to specific situations or just pure luck...