Why is undo closed tab only good for reopening one closed tab? That is quite limiting. Can you make it configurable so we decide how many we want to re-open, and potentially make it a parent menu with submenu that shows a list for us to choose which to reopen? I would like about 10 at least. Similar to the right click context menu in the file viewer, Undo.
For example, in Firefox, I can undo closed tab all the way until I reach when I opened the browser, or about 20 items, I forget.
Is it a random group of tabs you keep closing? If it's not, you can create tab groups in Opus. There are options to save or load them, which also could be done on the fly. Although it takes a bit of time to work yourself into the details. Especially the commands Go Tabgroupsave and Go Tabgroupload should be of interest, since they are best suited to create and reload "snapshots" of your current tab sets (e.g. Go TABGROUPSAVE "My Tab Group" to make some kind of snapshot).
I often need to restore and open a bunch of random tabs.I also have a strong need for this.
Imagine Firefox users waiting for every imaginable feature to be implemented exclusively by Firefox devs… 
That’s why browser extensions exist.
And DOpus "extensions" are somewhat created via its scripting API (which, FWIW, pretty much lets you do almost whatever you want if you invest the time to learn it).
Another aspect is, you would end up with a plethora of options and variations. Do you have five tabs to undo, or fifteen? Or as many as you want? What, if they were from different listers? Or you want only some of them reopened. What happens with the tabs that were opened after closing? Et cetera.
The idea isn't bad, but i guess it would be a great loophole for bugs and irritating things to happen. And the config files would have to be purged sometimes, after you have used hundreds of tabs, where each tab had its own state and position. Maybe a very basic option to reopen the last ten or so tabs in the same lister would be managable?
A while ago, I created a command that works kind of like this:
And that’s, IMHO, one of Opus best features: you can build commands exactly the way you want them if you just spend a little time learning its mechanics.
What I think is even better is, instead of asking for ready-made features, asking for more and better tools (e.g., the ability to create richer menus via scripting that support icons, submenus, etc.) so you can build your own exactly like you want. That benefits the user community even more.
What about a slider on a time scale, "recall" style for the tab actions? Move it back and forth to see your tabs animation. 
Yes, something like that, just a list to see the last closed tabs, or just allow us to undo closed tab many times until we reach the limit we set in the Settings or a limit of 10.
I honestly believe 10 is enough.
I don't use tab groups no. I don't yet have a need for it but I wouldn't be surprised if, in the future, I realise that it is helpful as it seems to be. But, not for undo'ing nor the purpose of this post (no offense).
I'm a new user so I really don't know anything about extensions for DOpus. I prefer not adding extensions (unless they'd never add x feature).
Firefox, yeah :D, been waiting a long time for tab groups, which they finally launched, screen tiling (split screen), move tab to an existing window, etc. They are very, very slow in developing actual useful features. They finally understood that they need to as many switched and I was about to as well.
Extensions ARE part of Opus.
As said by @errante, one of the most powerfull feature of Directory Opus is it offers every user the ability to customize it.
It can be as simple as adding an (existing and documented) option to a command in a button or combining calls to a few commands to embed in one single button or can be as complicated as creating new commands to do things very specific to your needs.
Once that command is created (potentially with its options or switches), it is available for you to use in buttons.
Not willing to use that flexibility in the customization will limit you in what you'll be able to do with Opus. Some things are not available "as default" but can be obtained easily with that customization. Opus will probably not evolve to offer something it can already do just to offer it "on the shelf".
If we come back to your request, it looks like the command developped by errante is exactly what you're looking for. Why don't give it a try?
EDIT: I also incite you to have a look around this help section and the button/scripts section to see what I describe "in action". Go and check the manual (Internal Commands [Directory Opus Manual]) to get a grasp at how configurable each command offered by Opus is.
Thanks for your reply. I think I did create a command to do the f5 refresh or ctrl f5, I forget, and assigned it to ctrl+r a few weeks ago during the trial.
I'm not sure how adding commands yet can do things that are not part of DOpus, but thank you for the info. I appreciate it but I don't think I'll be creating major commands on my own due to time limitation and experience.
@errante's command may work, I don't know, but how do I access that? He didn't share how or where.
I would still prefer this to be part of DOpus since the feature already exists, it just needs to be expanded a bit just to allow some more undos since I frankly do not understand why only one undo closed tab exists.
I posted it a few minutes ago, so just check it out whenever it becomes available in the Scripts section. Everything about how to use it is explained in the main post (the title should read: TabRescue ).
It's already here
If you just want to go back to the same folder(s) you were in, and don't care about the extra details like scroll position and selections, the built-in Recent list should take care of that.