So make something better that people will actually use--then the question of what to use will become a no-brainer. "Just use Foo." The "best" alternative to something like Cryptocat is Pidgin/Adium+OTR plugins, and you can't seriously claim they're as usable (nor are their implementations actually perfect.) If not that, then help to fix whatever issues the popular tools have. (They're open source, after all.)
Make formal security proofs, implement them, open source your prototypes, and have them vetted by as many cryptographers as possible (so one or two if you're lucky.) Then figure out how to market your product.
By far the hardest aspect of cryptography engineering is getting people to use your software in the first place. It doesn't matter how good you are at crypto if your software is never used.
It's very easy to criticize. Much harder to actually make more secure, more usable alternatives. (And, ironically, the people who ought to be doing this the most are much more hesitant to do so since they know of many more subtle ways to make mistakes.)
Make formal security proofs, implement them, open source your prototypes, and have them vetted by as many cryptographers as possible (so one or two if you're lucky.) Then figure out how to market your product.
By far the hardest aspect of cryptography engineering is getting people to use your software in the first place. It doesn't matter how good you are at crypto if your software is never used.
It's very easy to criticize. Much harder to actually make more secure, more usable alternatives. (And, ironically, the people who ought to be doing this the most are much more hesitant to do so since they know of many more subtle ways to make mistakes.)