the OO is offering not bad chances on victory for prussia, Basically the idea is that prussia has to be faster than france and russia.If you go for it, then go with strong forces (both supply trains and 6 generals).
The OO takes you closer to the historical course of action, because it was an offensive what the prussians tried in 1757 to take austria out of the war (until the defeat at battle of kolin put a sudden death to this plan).
and against the grain of the game as it was designed in the first place.
yes and no. The prussian objectives in bohemia were part of the design from the first minute (i.e. prussia always had 2 ways of winning: offensively and defensively). Playtest showed, that an offensive Prussian play did not decrease prussian chances on victory, while austria´s chances were decreased significantly. That´s why the OO rules were introduced.
All in all, the OO gives a variant to the *standard* game and opens up a new dimension. Prussian players seem to hesitate to go for it (which seems quite natural if surrounded by all these enemies). But it is worth a try, because you will see how the austrian player starts to sweat (he, who is the one with the most comfortable position), and it is really fun to send the prussian hordes down to brünn and tabor! -- The game will be totally different.