We are redesigning a site and some of the URL structure have changed in order to have a better content organisation amongst other things (many URLs were just in the root but now are under relevant categories).
Now some of those old pages have a pretty decent Page authority and are ranked at page 1 for their keywords and reading through some articles, there was a suggestion to not touch those URLs since even with a 301 to the new url (for e.g. /top-page.html to /top-page), the indexed pages will loose their ranking and page authority.
This kind of conflicts with what Matt Cutts said about 301 although since having never done it, another option we considered was keeping the old page as well as the new page and in the old page putting a rel=canonical to the new page rather than doing a 301. Will this second option help preserve the current ranking or is it just too much effort for something that won't make much difference?
Any pointers would be greatly appreciated. Thank you.