Have the option of video to video

Would it be possible to have the option of adding videos as well as photos? Or a new version that just does video?
I make demo videos of stock footage and have been looking for a program that would join many videos together with a simple transition between each, that would strip any current audio in the clips and replace it with an audio track of my choosing. The addition of adding a watermark would also be handy.
Like Image to Video GUI, it would save the need to use a video editor with a timeline and open up all of the videos and do it manually.
Thank you for reading my suggestion/idea :)