I already pointed that out, once defenses adjusted, he was garbage. His last 9 games of the season were well below average. I'm not giving him a ton of credit for running an over simplified offense in the first half of the season where he was completing a really high number of passes in safe areas, but not really doing anything to win games. He played mistake free football while the defense and running game won them games.
The first 3 of those last 9 games (assuming you are counting the playoff game) he was:
19/23 for 198, 3 TDs/0 INTs and a rating of 142.1 (home vs cle)
22/26 for 207, 1/1/96.6 (at atlanta)
23/32 for 310, 123.2 (with a near high in yards/attempt, home vs TN)
then the 1st buff game, which is kind of an incomplete for me
the indy game was definitely below average (26/45 for 299, 2/2 74.1)
the 2nd buff game was trash (14/32 for 145, 0/2, 31.4 YIKES)
but then he rebounded at end of reg season
22/30 for 227, 3/0, 128.1 (against a bad jax team)
20/30 for 261, 1/1 91.1 (dolphins)
24/38 for 232, 2/2 75.8 in playoffs (though if memory serves, a lot of the good stats came when game was out of hand)
So by my count that's:
3 very good games (cleveland, titans, jax)
1 impossible to garner anything from (first bills)
2 solid games (atlanta, miami)
1 below average (indy)
2 trash/cant win with that kind of qb play game (2nd reg season buff game & playoff game)
I'm not trying to dissuade you from your opinion, fwiw...to your original question about when to start questioning him this year - I told a few group chats I'm on that given they are installing a new blocking/offensive scheme with two coaches who are not exactly known for high octane offense that I'm withholding any judgement on Mac til last 1/3 of the season or so. yes there have been some accuracy issues so far - but how much of that is due to him pushing the ball down the field further? They need to move on from the dink and dunk offense and that isn't going to happen automatically, so I'm fine with them taking some lumps first chunk of games for dividend later this season and into the future. Some decision making issues from Mac so far too...is that just him? Adjusting to new coaches? Adjusting to new scheme? All of above?
I think if we are still asking these questions over last 6 or 7 games we aren't going to like the answers very much.
edit: i dont have nearly the recall of specifics, nor am I nearly as educated, as someone like
@SMU_Sox is on these things...so just kind of went on #s alone, which I understand is a bit rudimentary but in order to answer whether or not mac was "well below average" I think it suits just fine