I'd say with a better recruitment and training (which would have required better officers to do the training, so a return or retention of pre-revolutionary commanders would be called for) the French navy could have become a more serious threat to Britain. If Napoleon had invested anything like the means he poured into his army into his fleet, he could have turned out not one, but many Pomones. If he had kept in touch with the inventors of his day, he could have had shell-firing cannon. If he had for one second given thought to what he needed rather than what he wanted, he could have concentrated on facing the British fleet in his home waters. It would take more than that for the French flag to rival the Union Jack on the high seas (I don't think that'd be an option at that point), but if he had managed tp deliver a crushing blow to, say, the Channel Fleet in 1795-1800 he could probably have managed a more favourable peace. Britain might also be more reluctant to face him again.
However, the development required would have had to take place in the revolutionary era rather than Napoleon's own. Not easy.