The fields requested in announcing a new issue should use inline help information to explain to users what is being requested for each field. For example, currently full URLs are not allowed in the "Page title of the issue" field (T180984). Noting this inline would be helpful to publishers not aware of this limitation.
Yes, this would be a good improvement. Would you like to volunteer the texts, so a Google-Code-in-2017 student can make a straightforward implementation?
Maybe some strings of https://www.mediawiki.org/wiki/Help:Extension:Newsletter can be recycled / adapted?