Goff will be a good player but not as good as he should be
Even McNair given his tremendous physical talent underachieved. Fisher is simply bad with QBs and bad on the passing game and is actually overrated as a running game coach. (Although I will say Eddie George is one player that I felt played to his ability so you have to give credit there.)
But overall, if you follow Fisher's history, offense has been disappointment after disappointment especially at QB position.
As MAX posted.
just more of the same display of confusion and unpreparedness that you'd expect from a Fisher QB. But talent is talent and I expect Goff to do well (But not as well as he could with better coaching)