Every report I'd heard about him in camp said he looked very sharp and so naturally there was a sense of "yeah well let's see how he does in preseason" which was fair, except now he also did well in the first preseason game.
So now there's a sense of "yeah well let's see how he does for the rest of preseason" and again, that's pretty fair.
Rookies don't usually perform extremely well in preseason even if they end up good.
The thing I don't see anyone mentioning is how cohesive the Patriots offense looked while he was in there. He had a dumb rookie error when he drew a delay of game, but otherwise you didn't have the kinds of route miscommunications that we saw when Miami faced the Falcons. That's puzzling to me. You can say oh well the Pats have a well established offense...but established to whom? Ryan Mallett and the players he played with that night were mostly new to the Patriots. They've had no more ability to learn that offense than Henne, Bess, Hartline, etc have had to learn Daboll's offense. Yet, Mallett seemed to have full command of what was going on out on the field and Henne didn't, on only 8 pass attempts he threw twice to receivers running a route he didn't expect them to run.
This isn't necessarily Henne's fault, nor is it necessarily a Mallett > Henne issue. I've been saying that these players only practices the Dolphins had been running have questionable value, and I bet a players-only practice run by Tom Brady has probably the value of 5 or 10 players-only practices run by Chad Henne and Jake Long. I think we saw that play out in the first week of preseason.