I think community is very important because a large supportive community not only can be of help financially but also help in marketing & promotion of the coin. But apart from this support any bugs can be found out by them. This is especially helpful to the engineers who also get a morale boost. But all in all the personnel working on the coin is most crucial for product to be successful.
However most of the time this community are only bounty hunters that will dump the value of the project very soon as they get their respective coins. A good community is composed of people who are investors and holders of the coins because Im sure that they will not do desperate moves like bounty hunters just to get money.