A tool that blends two or more texture between each other using the RGBA channel. It blends between selected vertices, usually by selecting a column of vertex or a loop and then using the Radiant vertex color/alpha editing tool to set the value of the alpha along that loop/column/edge. (You may have to look up some video from BlackJackJonnyy)

• Keeping the tool having a classic feel while also having a more modernized approach of using all the RGBA channels.

• Another modern feature would to bring in the source 1 blend mask feature, this blending feature is extremely advanced but I do not think it would be hard to implement. You can look up (SOURCE Engine-style TEXTURE BLENDING! | Blender Tutorial) or ([Source 1] Hammer Tutorial V2 Series #26 "Will it Blend? Blend Modulate") for more information

• It can be somewhat more tedious to set up vertex color for objects in Blender and having to organize the color attribute data, there has to be a better way to do this while also keeping the metadata for the RGBA Channels when exporting to other game engine.

• Here is my idea, having two object stacked on top of each other but offset so there is no Z fighting and having a tool that makes this faster by setting up the textures to have the "Color Attribute that uses Alpha channel node that plugged into the alpha channel of the principled bsdf" and maybe when you want to use the object for blending you can click a button that set up the "Color Attribute" in the object data and shader node for that object so it ready to blend when needed. There is probably a better way to do this but this is all I know.