The Spartian hoplites are, firstly, 10 men more than the Athenian ones giving them the possibility to fight 4 opponents with 5 of their men. Secondly, they're stronger too (or was it tougher? better than a normal hoplite anyway) and thirdly, a four-star unit without leader is as good in this stat than a three-star unit with a three-star leader, as one star = nothing, 2 stars = normal advantage (12.5 morale), 3 stars = doubled advantage (25 morale), 4 stars = (50 morale) and 5 stars is , giving the unit 100 extra morale. So the advantage doubles with every star added, and 3 stars + 5 stars is only a mere 25 morale better than the 5 star-Spartans. And while your "normal noobie-hoplites" are weaker, they will not kill as many opponents and as such will suffer more from a morale loss (every kill gives a morale boost, less kills grant less morale regeneration).