I'll admit that my posts can get a little long winded... but I never said (or intended to imply) that a pump was NEEDED.
I'll also admit that I don't meet the OPs qualification of "people who have actually hiked a substantial amount of the A.T." Instead, my experience is with hiking a substantial amount of the GSMNP. I will also point out that I've very much still in the learning phase of using my Sawyer Mini.
But in the spirit of the OPs question of comparing a pump and no pump, I have found a pump to be MUCH easier when water levels are low... and most of the times that I've stayed at a shelter or campsite along the AT in GSMNP, I've just so happened to experience low water levels (i.e. nothing flowing from established pipes).