1.Can we apply textures to not just all sides of the mesh of a model or have a check box to turn that feature on or off so we can map certain textures to certain parts of the mesh of a model or unless the check box marked (apply to all sides of mesh) is turned on then do the opposite of painting textures to the model?
2.Can we have a easy model editor and creation tool?
Those are just a few simple suggestions, i would love to see in the update. (Note i mentioned a model creation tool as well as a model editor tool these should be plugins for unreal engine and unreal tournament)
XD 
The best way to map certain textures to certain parts of the models is to properly unwrap the UVs and have those UVs correspond to different parts of the texture file.
Why would you want a model editor in UE4? That’s an insane amount of work. There are plenty of great tools out there, including many for free. There are whole teams of people dedicated to just modeling tools. Same thing for a DAW for making music, and image editing programs like Photoshop. I would much rather they focus their efforts on the actual game engine side. Content creation should be left to content creation tools.
That said, there’s a sort of “light” model creation you can do in the form of BSPs. They’re just basic shapes, but they’re great for blocking out the level design while prototyping until you create finalized models.