Just the most valuable thing would to allow posters to edit their inputs for 30 minutes after original posting so errors can be cleaned up.
In other fora allowing this I have seen replies that dis not make any sense at all. Then you realize that the poster edited out what the reply was to.

If such a feature should be implemented (yes I have wanted to change on occasion) let it be a "postscript addition allowed" feature. This would allow a post to stay the same with a postscript such as "above, please read 4.7 uF, not 47uf". In that case a reply "C1 in your schematic is too large which would be totally erroneous after the 47 was edited to 4.7 would be understandable.

Erik