Currently, bash enjoys quite a bit of contextual help with through the bash_completion project.
This idea goes a step beyond: imagine a graphical terminal with a divided screen. The shell rests in one pane with a contextual help rests in the other. In a spirit similar to the Norton Guides of lore, the contextual help is available all the time or at the user's request. Different from previous systems, though, the contextual help changes dynamically based on the command and command history.
The contextual help can come from mining the bash history of the user (similar to how Julia Evans was extracting Git workflows automatically) or by using the command the person is typing plus its history as a special type of scenario-based Question. The command and history can then be issued against the database of man pages in the computer, showing snippets that match the context.
The devil of course is in the details and a successful implementation will require plenty of fine-tuning, lest it becomes a clippy for bash.