They released the game with this bug. We don't know why. Lets give them a bit of credit and assume they did not know about it, or assumed it was part of another performance issue that they had fixed.
So now they need to be made aware of it. We get hundreds of "stutter" threads, on all kinds of issues, sometimes it's referring to this issue, but they pretty much always got derailed by the hordes of !@#$%ers.
After months of watching the forums, this thread pops up, which attempts to specifically address this specific issue, and Graysdir and others do everything they can to keep it on topic... and it receives attention from a blizzard rep.
With me so far? There was a problem, it wasnt known, it was brought forward, and acknowledged by the people who needed to acknowledge it. Hell we even got confirmation that the bug was reproduced, that's pretty major.
As far as I am concerned this is highly appropriate for both bliz and the consumers so far.
Now it's unknown where exactly this bug is, but you can be pretty much guaranteed it's in a sensitive enough place to merit extensive playtesting to ensure that it's not going to potentially affect a large amount of players in a negative way. This process alone can take weeks. As for diagnosing and fixing a bug of this kind, there's so many factors involved, the best anyone can do is a blanket timeframe even to get to a point where feedback can be made. I'd say a month to a month and a half. There's other factors, such as patches. If a large patch is coming up (which seems likely), then it would make sence to leave the fix to be tested along with all the other engine modifications to be present in that patch, so it's even less likely to recieve an update in that case, at the very least until the patch is announced.
That said, alot of what I'm seeing since the last milestone is highly inappropriate. I do believe blizzard should acknowledge a bug of this nature, and they did. I however in no way believe that they should keep us updated as we see fit. Sure, I'd love to hear an update, it would be really, really nice, but to demand or expect it at this point is just absurdity and/or entitlement. After a month and a half, or after a major patch, it would definitely make sence to ask after that, but even then, politely and patiently. Then if there's no answer after another month or so, it would be somewhat appropriate to get impatient and a bit angry. But this is not that time, nor do I expect it to come to that.