That is a challenging question. It is no doubt that Coriolanus was a effective soldier and commander of troops. A country needs strong military leaders if it hopes to succeed. The truth of this is what is feared when Coriolanus is gone and the Volscian army is set to march against the city, as seen in Menenius' fear:
Pray now, your news?--
You have made fair work, I fear me.--Pray, your news.
If Marcius should be join'd wi' the Volscians,--
However, in terms of leading a young republic, Coriolanus is not the man. He does not "play well with others", if you will. He does not know how to keep his anger in check when others exercise free speech, and believes too strongly in discipline and duty to understand how to accept the decisions of the crowd. The inclusion of his mother Volumnia in the play is proof of this. Coriolanus will listen to no man, but he will listen to her - suggesting that his first "leader" will always be his "leader". He prefers a dictatorial state.