Everything you posted is his volume stats, which is my exact point (except for Interceptions, where you're flat out wrong on... Stafford is always among the league leaders in INTs).
YPA is average. QBR is average. Passer rating is average. TD% is average. INT% is average. TD:INT ratio is average. Has like the worst record in NFL history against good teams (3-31 record against teams with winning records). There's almost nothing to suggest that he's a good QB unless you care about the sheer volume of his numbers, but all that really suggests is that he throws the ball a lot.
Compared to Dalton: Dalton has a higher TD%, higher INT%, lower TD:INT Ratio, higher passer rating, and probably a lower average QBR. All of their numbers are nearly identical. Stafford just throws it more.