As I posted on other thread the ideal TVM for me would be pretty much exactly what DB have. It's simple for those who don't know how to use it and equally importantly fast for those who do, as well as being able to offer much closer to the full range of products a ticket office can such as rovers, reservations etc. It has a journey planner if you want one, but it isn't needed if you don't.
Would probably also be helpful for many to have Plusbus more prominently displayed at the end of the process, perhaps a visible logo rather than a tiny "add +bus or admission" button.