I completely agree that there's nothing at all wrong with folks hoping for a statement from Jake on this. In fact, I think it's very reasonable from the perspective of serious Brokies. And, I'm pretty much in the camp of folks who would really like to hear from Jake. For me, it would help produce some sense of "closure" for me. As it is, whether it's reasonable or not, I know that as a Brokie I'm personally waiting for Jake to do or say something.
But, I don't really see an analogy between the current "wait-and-see" ambiguity going on in terms of Jake and his reaction to Heath's passing and the "lessons" of BBM (of which, it could be argued there are many... the "lessons" of the film/story are just too complex).
But, I do think that Heath and Jake playing the two main roles in BBM is extraordinary (extraordinary in terms of cinematic history at least, and probably in terms of personal bond... given the evidence that Jake's Matilda's godfather, etc.). These two actors will always and forever be linked together in the public mind and in cinematic history for generations. And, now that Heath is gone, BBM is the most substantial and extraordinary film in Heath's short career... so, BBM takes on even greater proportions when Heath's career is considered on its own. It just seems important to have folks (and probably most importantly, Jake) from this extremely important film to Heath's enduring cinematic legacy, mark Heath's passing. So, in that sense, I think it's perfectly understandable why there's some confusion and even frustration about Jake's withdrawl from the scene to such an extreme degree and his lack of a eulogy type statement so far.