Remember: Engines like Unity and Unreal (and maybe even Godot) have teams of considerable size developing them. Panda doesn’t have that, I believe.
That is a point worth thinking about, I do feel.
My own response is that different editors may serve different developers and different projects. Thus having multiple editors provides developers with options as to which tool to work with, potentially allowing them to choose something that works better for them and their project.
Right, other more commercial engines have larger teams, even Godot has substantial fundings to have full time developers work on their engine and tooling. As for panda, except for the as far as I know small core team, there is only the community doing work voluntarily.
As @Thaumaturge already said, it’s worth thinking about indeed.
The problem I always faced with the earlier made editors were, they either didn’t work out of the box or were old and unmaintained. I’m not even sure if the people creating some of them are still in the community. But as they were mainly open source projects, we can take parts of them that were useful and integrate them in the new editors.
Another problem we also face here is communication and marketing these tools. Some people starting editors because they may not even know there were some in the beginning. Digging through age old forum posts is nothing you want to do to find an editor for an engine.
If you did do that and found one of the editors, you still need to know how to run it since most of them only came in source versions, no binaries you could “just run”. So you had to install dependencies and possibly even fix things to run them on your system.
So if we want to have fewer editor endeavors spawn every year, those are some of the points that have to be tackled first. We need one editor that people know, one that the average panda3d user wants to use and which can easily be enhanced for the more advanced users. And, it needs to “just work” on any platform panda3d supports development on. Then it could even be integrated into the engine as an optional installation step for the users to be just there when they need it without searching for it somewhere else.
With all that, people will flock around that tool and help enhancing it which is the best way for open source tools to sustain, they need contributions from other people, be it code, testing, translations, documentation, all those steps and more would make the editor better over time and not get abandoned as so many editors that started out good have become.
For me, I do plan to continue on FRAME and all its editors for the foreseeable future, but I’d also love to see it being integrated more tightly for others to discover as otherwise this may stay a one-man-show and won’t grow as quick as the engine deserves.
Agreed!!!
I really want to help you.But I am a noob… 
Well, if you want to help, you can do so by just try using it, telling me, where you got stuck and where it’s not intuitive. For that, you don’t really need much knowledge as it should be beginners friendly.
I haven’t got to write much documentation yet though as I’ve planed that for when the first beta release is officially out (got a little stuck creating the installers) but as the feature set is not that large yet, you should still get into it rather easily and you can always ask if anything’s not clear.
You can also tell me about specific features other engines have you’d like to see getting integrated.
I am really busy recently.Sorry for taking so long.
I’ve tested the scene editor roughtly.And there are a few issues.
1.Open file dialog doesn’t have a path browser button.
2.Open file dialog will crash when we press enter after copy the file path with file name into the text box.
Wishlist.
1.Could you please add a function which can drag scene by the coordinate system which is on the topleft of the editor?Because the scroll wheel of mouse always very fragile.
2.Animation State Machine.Both 2d and 3d.Maybe we can make a system like the Advanced Locomotion System of UE4 with it. 
3.Node based editor.Maybe we can refer to the layout of Godot,we can switch 2d and 3d scene easily. And we can add nodes to implement some function,such as Animation Tree,Animation Player,Navigating System or etc.Panda3d is also node based.So I think there are many common things between Panda3d and Godot.(Maybe I am wrong.)
4.Scripting support.I have learnt how to make a simple 2D game with Godot.I just find that the design of Godot editor is very easy to use.We can make scene and write code comfortably.
Again,your work is very uplifting.Please keep your good work!!!