The biggest problem with those statistics is the passing efficiency (YPA) on throws under 2.5 seconds. You wouldn't find that for the league's better QBs, and it's the primary reason for the offense's inadequacy. That doesn't necessarily mean Tua is to blame (although he might be, at least in part), but it's certainly a problem with regard to fielding an adequate offense.
I think the stats on the over 2.5 sec throws is also pretty alarmingly bad especially when compared to the under 2.5 sec throws. Certainly any QB is going to be better with the under 2.5 sec throws, but this much of a disparity is a problem.