I don't see what the fuss is all about. BM is very intentionally built so that individual characters can very often not do what they please, and need others to cooperate with them, even if they hold the highest offices.
It creates conflict, communication and teamplay.
In this case, Tom, if a ruler (Noble A) wishes to become lord of a vacant region, and Duke of a new duchy based in it, the following steps need to take place:
- Duke (Noble B) appoints Noble C as Lord of region
- Ruler elevates Noble C to Duke
- Noble C steps down as Duke and Lord
- Ruler appoints himself as Duke
- Ruler appoints himself as Lord
It's pretty cumbersome, especially the third step there.