Actually broken SD card and inability to root without tripping Knox is huge reason for me and frankly I can't imagine any bigger reason not to update, unless the new update would completely brick it, but this is close enough.
For most of us here KNOX should be a non-issue.. Unfortunately when buying a Samsung device it's something we have to expect. I expect shortly that ALL root methods will trip KNOX. It's a security feature and root is nullifying that security.
If your company requires KNOX then you probably shouldn't be rooting it.
As for the warranty bit, we have been voiding warranties since the beginning KNOX doesn't change that.
As for the SD card that's another thing that is fixed 1 2 3 by root. Again for most of us its a non-issue.
Sent from my SM-N900T using Tapatalk