According to PFF Bakhtiari allowed a total of 29 pressures (6 sacks) on a total of 585 passing plays for an efficiency rate of 96.0, which ranks in the top third of all tackles.
The pass protection was excellent last season, that doesn't work with a LT having troubles in pass protection.
I have a couple of issues with judging pass pro as a ratio of pressures to pass snaps.
First, that approach gives equal value to sacks, hits and hurries, when in fact there is a sharply lower value in a hurry vs. a sack, with hits somewhere in the middle.
Second, it does not account for penalties, which have a lower value than sacks, but a higher value than hits on balance. 10 and 15 yard penalties are typically drive killers.
Bakhtiari had 11 penalties of 10 or 15 yards in 2013, 3 of which were declined or offsetting. He had 8 such penalties in 2014, which is an improvement but still a questionable number.
For comparison, here are the 10 and 15 yard penalty counts, including declined and offsetting, from 2014 for the rest of the Packer offensive linemen:
Sitton: 2
Linsley: 3
Lang: 3
Bulaga: 2
If Bakhtiari wasn't quite so grabby, the sack count might be 10 or more, which is quite a lot.
I would not regard Bakhtiari as a top 1/3 pass blocker among starting LTs. Perhaps average or somewhat below, while also not being a particularly strong run blocker as you have observed.
In light of those who came before him (Newhouse, the human turnstile; Sherrod who never learned to finish blocks even when he was able to play), Bakhtiari is a godsend.
I certainly wouldn't call for his replacement, and he's good enough to win a championship given the strengths at the other O-Line positions.
But being thankful for his presence in light of the recent alternatives should not grant him a higher objective value than is warranted.