In the seventies BMW used to use shows to release new models.
Of late, their Modus Operandi is to release a new model in between bike shows, allowing saturated coverage by the magazines, which relates to a fair amount of free advertising and attention by potential buyers.
The Northern Hemisphere Spring time, would be the best bet for timing, to either release details of a new model, or, to just release it.
As for the 30Kg weight reduction, an obvious one would be a digital ABS system, allowing possibly 2Kg straight away.
Things like that, are what is now driving the car world to lighter and more fuel efficiency, along with re-cycling of more of the components which usually means more plastics, which in turn means less rust.
In short to achieve the possible 30Kg weight, they need to lighten every component by 12.5% as this is, in some cases, not possible, then some things have to achieve a greater weight reduction whilst others only nominally or not at all.
I myself see no problem in reducing the current 1150 machine using some lateral thinking, which I think the engineers who have been producing the latest crop of BMW's are doing.
As the Chinese are once reported to have said, "We live in interesting times".
Mick.