The April 1st update is an exception due to fact it was removing features only available on one model, but it serves to highlight the flaws in firmware release processes, and the way firmware is updated. The most glaring one being why is it necessary for such a large update to disable an already disabled feature on the slim. Maybe it did other undocumented things too, I doubt that in this instance as it seems that firmware release was rushed out for fear that the pirates had set sail for PS3 land and the release we have now is the one that was originally scheduled to be the next update.
They need more structure to their release cycles - stick to quarterly releases for example - and they need to sort out the firmware updating process so that you’re not having to download the entire firmware image each and every time.