You mean an custom startup blender? I thinked about this yesterday. lol I can share my startup .blend (it's pretty custom for game dev). Actually I also tell to all my audience to create the same default as mine (portuguese +BF bge video, but It's the same for UPBGE):
https://youtu.be/Bes42OKqiH8
Edit: If the logic bricks goes out, the way we create games will change a little bit. So we will need to rethink the default UI.
my startup blender is a bit different:
right side bigger: yes
bottom part covers the entire width of the screen and is game logic, that way the properties end up under the right side, in the corner.
i don't change the scenes part, instead i use the right side for text editor (hence why it needs to be bigger), properties editor, and whatever i need at the time. having the text editor menu in the middle of the screen is more "comfortable" when selecting text files and using menues than having to move the cursor and looking to the bottom of the screen. properties menu has the buttons at the top.
i agree that upbge should be blender game as default instead of blender render.
default fullscreen resolution could also be changed from the arcaic 640x480 to something more modern, maybe not 1920x1080 but something like 1366x768.
my screen resolution is 1920x1080.
Some note for the startup (discussed with @UnidayStudio) :
More ideas:
Create Component) ;I tested a startup:

File:
startup.zip
There's also profile and render queries enabled by default.
About the theme, do someone have something a little bit darker ?
Any feedback is welcome.
Looks great!
As it is very redundant with the current Game Logic layout, what about replacing the Game Logic screen layout with this, rename it to "Default" and rename the current Default layout to "Modelling" or something like that? This way we would also preserve the current Default layout which is very handy for modelling or similar tasks.
And please move the Info Bar all the way to the top (look at the small red "x" in the top left corner of the following screenshot, the marked area just takes away place). But this might be caused by my theme so if you don't have this problem just ignore it, I will move it manually then.
Also, I think the cube could do with another color:

A set of 2D filters packed in <-- putting down an idea.
Great. I made some changes:
These changes was based on my personal experience using UPBGE + what I use to teach in my channel.
http://pasteall.org/blend/index.php?id=50182
And I agree with @Momel15 theme suggestion and also with removing the Game Logic Layout (this is a Fork about making games, Game Logic should be default :smile: ).
@adriansnetlis Gave a good idea about 2D filters, but I've to remember that isn't good to create a startup file with too much data stored in. And It's also always good to deliver a 10/10 rating stuff to the userbase, so we need to choose careful the shaders. My suggestion is to wait until the next UPBGE version that will came with multiple render outputs) I can make something. (Alctually IMHO Post processing should be a default thing inside the engine.
@panzergame It's hard to find you online, you could create a Discord :smile:
Good work :)
What about exposing the outliner ?
Other than that i though to setup the cube as a static box and the plane as a static triangle mesh.
I created a Discord channel for UPBGE: https://discord.gg/8QBxEyB
@panzergame I almost never use Outliner. But I know that it's a bad idea to made decisions based on one user. I'll made a small survey about this (and probably other things as well).
@Momel15 Could you please provide us the theme that you made?
Could you please provide us the theme that you made?
It's not by me, I didn't upload the screenshot above to show the theme in the first place, it was about showing the cube's color and default layout, so I don't know if we can use it.
But anyway, here's the theme: http://pasteall.org/1083958/xml
But I'm not sure about copyright, as I said it's not made by me and I don't know the original theme it's based on, but I modified a lot (it actually might have been made by me but I can't remember it anymore :D)
Most helpful comment
Great. I made some changes:
These changes was based on my personal experience using UPBGE + what I use to teach in my channel.
Download Link:
http://pasteall.org/blend/index.php?id=50182
And I agree with @Momel15 theme suggestion and also with removing the Game Logic Layout (this is a Fork about making games, Game Logic should be default :smile: ).
@adriansnetlis Gave a good idea about 2D filters, but I've to remember that isn't good to create a startup file with too much data stored in. And It's also always good to deliver a 10/10 rating stuff to the userbase, so we need to choose careful the shaders. My suggestion is to wait until the next UPBGE version that will came with multiple render outputs) I can make something. (Alctually IMHO Post processing should be a default thing inside the engine.
@panzergame It's hard to find you online, you could create a Discord :smile: