A lot of problems I see with new-user posts are code blocks (obviously not the sole problem, but bad code blocks tend to make questions look worse than they really are).
Firstly, can we bring in triple-tick code blocks?
Indenting pasted code is a pain...
var theRest = "... and triple-tick blocks don't have proper formatting.";
This is tricky for certain new users because most code review tools many users are familiar with (GitHub, Phabricator, Slack, etc.) use three ticks instead of indenting.
Further, indenting code requires highlighting it and hitting the {}
(code) button in the editor, which I'd assume isn't directly apparent to certain users.
As well, if we adopted the ability to specify a language much like GitHub does, it'd benefit the experts as well since we wouldn't have to remember the weird <!-- language: xyz --->
syntax in the event small code bits don't highlight correctly, which makes editing questions to correct such issues much easier.
Second, screen widths are not a problem anymore. CSS media queries exist, too. So why are we putting previews below the question input, especially since the user can re-size the question box? This causes the page length to grow at 2x the speed of typing.
I know this would have to be A/B tested, but I hypothesize being able to always see what you're typing while you type it would decrease the countless formatting problems new users seem to throw in there.
In the event the screen size doesn't adequately allow for a side-by-side view, use a media query to revert back to the old layout.
Third, we should be warning the user their issue may be the result of an indentation problem or a typo. We are a coding site, after all - services like SourceGraph can do it quite reliably.
This system could also be used to better enforce (warn) about SSCCE's - or the lack thereof. We have the technology - we should be leveraging it!
Static analyzers/linters exist for every language out there, and even if the service on SE's end has them configured to only check a few things to trade for speed improvements, this would cut down a LOT of bad code blocks I've seen.
As I mentioned, code blocks aren't the only problem of course - however, in my experience, bad code blocks are indicative of bad questions, especially with new users. A lot - not all, but a lot - of the problems with said code blocks come from typos or things that linters could easily find, and we all know how impossible it is to help a user with bad coding examples.
StackOverflow is, after all, a coding site. If a question has poor English (as the case frequently is) but good code, it's generally still very answerable and the OP is generally quite happy and responsive to critique.
Most posters can read code better than human language, anyway - so let's allocate some focus on the code itself.