I should have made it clear that I didn't mean 'good' from a moral standpoint or anything like that. I meant 'good' as in 'effective'.

In other words, would Tom have been able to take the Corleone family forward? Could he have protected the family from those trying to challenge thier power? Could he have made the family's business as successful as Micheal made it? Could he have turned the family legitimate? Would he have been able to keep his family loyal?