In nearly any field there is a number of important results which look obvious to experts post factum but somehow are not that easy to come by in the first place (e.g. in mathematics some important definitions look exactly like this). Unfortunately, this apparent post factum simplicity makes conveying the importance of the idea to expert audience (and in particular to the journals' editors and referees) very difficult. To make things worse, sometimes the author is unable to illustrate the application of the idea by sufficiently striking examples.
The question is whether it is possible (and if yes, how) to mitigate this apparent post factum simplicity in the talks and research articles, i.e., what can be done to adequately convey the significance of "post-factum-obvious" results to the audience and, in particular, to get these results to the journals they truly deserve?
I am particularly interested in the advice applicable to mathematics/mathematical physics but the suggestions suitable for other fields are very welcome too, as the situation in question does not seem to be all that field-specific.