This has been coming for quite some time. Each new version of the 4.x line had something to improve security for the average user, usually in the form of restri

This has been coming for quite some time. Each new version of the 4.x line had something to improve security for the average user, usually in the form of restricting an API access or changing filesystem rules. The rules revolving around /system are a huge security issue, as you can take any permission you wish without having to inform the user. Malware authors take advantage of this. Unfortunately su binaries install to this location for the same reason. Devices with easy to unlock bootloaders (e.g. Nexus line) or an official program to unlock the bootloader (e.g. Morotola Bootloader Unlock program) won't have much of an issue, installing alternate recovery isn't terrible on those devices. The more troubling aspect is those vendors and carriers that offer no such thing. Those vendors/carriers view the phone as their property on loan to you and that they should retain control, for whatever reason. For 90% of users, this doesn't matter, they don't bother to do anything that requires root. But the other 10% are finding their options squeezed unless they buy from specific vendors and sources.