I am optimistic that we will see those higher-end tools in tablet form sooner, rather than later. All it would really take is a step up in multi-touch precision. Steve Jobs has famously ripped on the stylus, but to have fine pen precision (like Wacom already offers) in additional to simple finger manipulation could end all doubt about a tablet's ability to replace a PC. It could switch from writing/drawing/manipulating with a gigantic crayon, to a fine mechanical pencil.