In my opinion the problem with the Jacobites lay in the time that the '45 happened. The Catholic Stuarts had been exiled for nearly 50 years by this point, most of their main supporters are either dead or in exile and are unlikely to risk their heads on a dying cause. Sure there was English Jacobites but none of them wanted to rise until they were sure that the Jacobite cause would either win or had a high chance of victory. Charles Edward Stuart himself was highly personable and able to rally people to his side by personality alone, even when he had no French army when he landed in Scotland. I think the best thing would have been for his father, James Francis Edward, to have had a personality like his sons. A charming leading personality, combined with the '15 rising, could have resulted in the Stuats being restored or at least taking Scotland. Sadly however, James was a very depressing man, who was, like his father, unable to really inspire loyalty or hope.
I will say however, that I read in a bio of Bonnie Prince Charlie that his invasion of England sent shockwaves through the financial system in London and could have destabilized the entire financial nation IT also suggested that if Charles had pushed on to London many of the merchants and financiers might have made a deal with the Jacobites to save their financial future in exchange for supporting them (the Jacobites). I'll have to re-read that chapter but it seems to me that the '45 could have been more successful then we think.