Just like what I did with my Generations Blaster, I turned Motormaster into headmaster. I just removed the ball joint and made a hole for the Titan Master figure to fit in. I used Crashbash.
Why not? Maybe the other poster just think it looks like a waste of a motormaster (especially if the change meant destroying any head joints, etc). This would be further compounded by not repainting the fig?
I'm assuming you are asking why it needs paint. So I will answer. The two purples don't go together. At the very least with his Master Blaster thread the colors were consistent. I like the idea behind this custom but it needs improvement, and I'm telling him what I think should be improved.
I don't know about you, but if the entire point of the mod was to turn Motormaster into a Headmaster then the OP did exactly that. I don't think Crashbash being used as the example head has a lot of bearing into that.
So given Solrac333's history as a customizer, I think we should give him the benefit of the doubt that there may be more coming. I suppose the cockpit could be in the back, in the Semis sleeper compartment.