If Greece simply defaulted on their debts, would the results for their economy be worse than any other options they are facing?
I don't think so. It may be more difficult in the short term but with the ability to devalue their new currency, with time, they could grow. The Troika option is just driving them into a cesspit; and no way out, and it would mean privatising all their collateral goodies. This means the rich elites would buy them and make a fat profit off them, leaving the Greeks as serfs.