Hi Gary,
thank you for taking time to write this, very appreciated.

Allow user to separate single and group(dynamic) redirects through the interface(like a view for each maybe separated by tabs on Redirect page) with group redirects prioritised through software, not the order. You may need to add an override option for extreme cases

I'm working on something like this, not sure if it will be another extension. ReDJ and Tag Meta work on reg exp, so it is not simple to add literal matching that work together well.

The ability to start creating a redirect from the error page

Same problem, this can be done when it supports literal redirects.

Add another filter to error page for "Type" so you can easily filter out 500s or 404s etc.

This can be a good idea, if you need to have different looking pages depending on the error class (4xx, 5xx). But I'm not sure it will be widely used, but to have more macros for customizing error page is already in my wish list.

Improve comments to render line breaks and adding/editing a comment directly in Redirect list view

Added to wish list.

The ability to start creating a redirect from error page

Same that first 2 points. It will be a "surprise"...

Include a link directly to your plugin from the component

Ok. I will change the plugin status label in a link...

Add an option to design error page through standard Joomla article (this should include plugin support)

There's a macro to get the article content by id, and use it in the error page. It is not so easy to render the whole error page as any site page, cause I should render any piece (modules) like Joomla do...

Kind regards,
Luigi