I came to a realization after Hell Bent. Now this will only make sense if you've watched the 90s Canadian animated series ReBoot. The classic version of the Master is Megabyte, suave and intelligent. Whereas the modern version is Hexadecimal, chaotic and completely insane.I agree. I don't think the Master needs to be so over the top. Just make him/her a highly intelligent Time Lord who wants to do bad stuff which the Doctor would obviously want to stop.