How would you make the bash manpage short and to the point, considering the complexity that it implements?
13 pages of the 80 page manual are devoted to readline and programmable completion. Readline and programmable completion could be removed from the shell, and their functional equivalents moved to a more logical place in the terminal emulator. Plan 9 does this, and it works well, and people seem to like it and the flexibility it gives.
24 pages are devoted to builtin commands, many of which are unnecessary duplicates of regular commands, and several unnecessary altogether.
3 pages are about weird parameter expansions, all of which can be done more intuitively with sed, except for the array one, which can be done with awk.
And there are many smaller things as well, like biffing or arithmetic evaluation, which can be done with dc or whatever. You could try moving history out of the shell and into the terminal emulator as well.
$ man bash | wc -l
5351
$ 9 man rc | wc -l
496
$ help "*"
will print out all shell built ins (list help for them). And if the short description is not enough, go google for each.
This is how I learned unix shell back around 2000ish. Aside of giving an excellent insight into zsh, it also gives many good hints and notes about unix shells in general.
The guide is in some serious need of a good editor to make it more concise and better organized. It also needs many more simple, practical examples. Unfortunately, it hasn't been updated since 2002, which also makes it a bit obsolete, since zsh development has been very active since then and zsh is now on to a new major version.
Overall, the guide is a nice try, but zsh needs more and better documentation if its not going to overwhelm all but the most dedicated users.