If TB would offer "date thoughts", it could be that easy. Just select a thought with date information, and tell TB: "this is a date thought". That's all. [Just imagine this function, using the selection list!]
A thought can stand for anything - a book, a letter, a date, a person, a company, an event.
When I use TB, my focus is mainly on the plex. Second priority are the notes, third the attachments.
I admit that I think along the same lines ("date" being an attribute, or a type, of thought).
But to me the timeline still has its high value as one of the data visualisations TheBrain must offer.