Confidence in the language is adversely affected when applications which have run happily for years suddenly stop working.
Those other things that you list are nothing but minor gripes by a small number of developers who suffer from OCD. None of those things stop competent developers from writing perfectly adequate applications, so they cannot be classes as showstoppers. What CAN be classed as a showstopper is when a website owner cannot upgrade to a new PHP release because his application won’t run.
We are working with Enterprise solutions as well, and we cannot wait until the new version is released due to massive improvements to the internals, both for the speed increases and making it easier to make extensions. This alone should be enough for anyone to update their code base if they are using any of the functionality that is removed.
Those would be welcome improvements, but if I cannot run my existing application under the “new and improved” version of PHP then it makes it nothing more than the “new but unusable” version of PHP.