I remember the moaning about Touch ID at launch, so I'll take everyone's comments with a pinch of salt. Usability is key to what Apple does, they even stress this to us in service documentation that no customer ever sees.
What has me slightly concerned is Touch ID's nascent adoption on macOS. Some people went for Touch Bar MacBook Pro models specifically for the feature, and others (like me) want it on a Magic Keyboard for use on the iMac/Mac Pro. Apple sending out messages of its replacement with Face ID is going to surely lead to developers questioning whether to support it in their Mac software in anticipation of Face ID coming to Mac in due course. iOS 11 code mentioned iPads and iPods having Face ID, so it stands to reason Apple would homogenise it as an overall product feature.
The only saving grace it may have is that no current Mac could use Face ID, and replacing a flagship feature barely a year after its debut would p*ss off a lot of people and rub the wider savvy Mac community the wrong way for sure.