It's interesting that you single out that shot for criticism, since, even speaking as someone who's never loved
Taxi Driver as much as the general consensus, I've still always felt that that scene was probably the best in the film, and the way that shot plays out is part of the reason why, since I love the way that so much plays out in a single tracking shot, with the camera following the taxi/Travis all the way from the sidewalk to the first building's stoop and then to the other throughout all the action, never cutting away, but patiently letting the tension steadily build up throughout the shot, and any cutaways to close-ups would've likely only broken my sense of immersion in the scene, IMO.
Instead, if I was to criticize any scenes in
Driver (besides the ones featuring unnecessary
racial stereotypes), it'd be the ones like when
Travis chatted with Sport earlier, where the somewhat slack pacing makes it feel slightly more dramatically inert than it should've, which keeps the film from being as consistently engaging to me as, say,
Raging Bull (although all that means is that Driver is "just" a 9-out-of-10 movie for me rather than being a straight-up
10, so it doesn't hurt the film a ton or anything). It's not a matter of the average shot length being "long" when measured by modern standards, though, as
The Departed supposedly has an ASL of less than half of
Driver, and I still found it to be pretty stylistically obnoxious at times, so I'd say it's more an issue of finding the right overall balance for the film in question; some go too far in one direction, some go too much in the opposite way, and some find the perfect ground in the middle for their own purposes.