In general, I wouldn't say a hand-drawn scheme is the end of the world.
A literate and clear sketch done by a hand is perfectly fine, and if the person doesn't know how to draw properly, no software would help.
On the other hand, a user can definitely be offered with a variety of programs, and the community already has the list: Resources for learning Chemistry::Software.
I wouldn't force a single program (especially not ChemDoodle [Web] which I personally think is just not that good, but many love it for its primitivity and accessibility).
If I did an edit including redrawing the reaction scheme with a computer program, I sometimes leave a program's name in edit's description.
Similar topics have been raised before, e.g. How to draw structures of compounds while writing questions? A good point mentioned there: a user should not be punished solely for providing a hand-drawn image (given it is literate, relevant and readable), and also one should keep in mind that redrawing such illustrations is often a time-consuming process, and isn't always considered as helpful as, for instance, typing text from a screenshot.
The latter not only prettifies the post, but also makes it searchable, whereas the redrawn image still remains an image.
Finally, I would like to encourage the community members who know the drawing guidelines (those by IUPAC, by the way, are available for free), are in posession of good software and are familiar with ACS style to participate in editing or improving existing posts.