well.... I wouldn't say insane, I think it might not be the wisest course of action. The second issue that resulted in the Note 7's demise, would appear to be more subtle than the obvious manufacturing defect that caused the first one. My guess is that it is related to some design decision....
Now, this means a little bit of trouble for the S8 since Samsung does a two-step when it comes to designs... as they take elements and bounce them from the S line to the Note and back. The all glass construction of the S6 begat the all glass Note 5, the Note 5's reverse curved back got brought to the S7... it would be safe to assume that the S8 might share elements from the Note 7.... and whatever design defect caused the Note 7's cancellation might be among those.
This is a nuance that I am sure is not lost on Samsung... the investigation is probably 'all hands on' at this point.