What type of leader is Piggy in Lord Of The Flies?

It is a pity that Piggy's attempts at being a leader are largely unsuccessful firstly, because of his appearance - he is overweight and wears glasses, secondly, he suffers from asthma and thirdly, he had been made fun of from the outset when the boys heard his nickname. Especially Jack's derision towards him encouraged the other boys and they mocked him. No one could respect him after that and even his most sincere attempts were seen as snivelling gripes only.
As a leader, Piggy would have used a common-sense approach. He is clearly practical in his thinking. He is, for example, the one who, at the start, recognizes the practicality of the conch and suggests that Ralph use it to summon whoever else might be on the island. He also insists that it be respected and puts forward rules to that effect, as such, it becomes a symbol of order and discipline.
Since Piggy is orientated towards rules and discipline, he would have formed a more functional society than the one Ralph and Jack did. He most probably would have established a system of rewards and penalties for those who did and did not adhere to the rules.
Furthermore, Piggy would have created clear tasks for groups amongst the boys, as Ralph tried to do when he and Jack decided on who would be hunters and who not. In such a system, the boys would have had more purpose and their society would have had greater functionality. 
Piggy's style of leadership would have been outcomes-orientated for he focuses on what has to be done throughout the novel. He is the one who Ralph and Jack leave behind when they go off to establish whether they were on an island. It is also clear that Ralph recognises his intuitively caring nature when he also later suggests that he should be the one looking after the littluns when they go looking for the beast, although he also states that it would be best for practical reasons since Piggy is not healthy enough to accompany them. Piggy's leadership would probably have ensured a 'safety first' approach, especially with regard to the littluns. 
Piggy's 'old school' approach in which authority is respected, would have achieved a more disciplined society and there would have been greater order and control.
In the end, it is tragically ironic that both Piggy and the conch simultaneously cease to exist. His death and the destruction of the conch introduce a state of anarchy in which the boys become true savages and their innate brutality is given free rein.