I used it too. I know there were changes by ASUS to nvram that made maintaining the script very tedious, if not impossible. I think each field now has varying links.
The only real complexity to full reset and reconfigure for me is that I assign a static IP to all the devices on my network. However, thanks to some helpful users here, there is a simple workaround. It should only be used on the same router version, do not migrate. Look at both post #74 and well as this post #75 in the link.
https://www.snbforums.com/threads/backup-manual-dhcp-list.12876/page-4#post-469462
I have ovpn files from my VPN host, and keep most other settings in a text file linked off my desktop that syncs with my phone and tablet for handy reference. Makes updates much less time consuming. As stated many times, backup both router and jffs using the ASUSwrt-Merlin webGUI tools. Another step I make before upgrade is backup my jffs partition and my entire USB stick to my computer using and FTP client. I am a firm believer in repetitive redundancy.
Easy backup and, if necessary, restore since I am an long time geek and primarily use Linux, all permissions are preserved. (I have an old Win7 laptop for those few items I need that only work with 'Doze)