I completely agree with Slogger and Talisman. This is purely subjective.
I have experienced bats which the guys in the shop said had a good light pick-up for the weight, but when I picked them up they felt heavy.
For my first Warsop, I just told Tony that I wanted a bat which felt like a 2.10/2.11 but make the biggest bat he can with such pick-up. The bat I got, was a disaster as it felt so heavy. When I called Tony and explained him the situation and find out what was the problem, Tony finally asked me the question " What is your weight, height and built". And here was the answer to our problem. Tony is a big well built guy and I am probably 80% of his weight and a few inches shorter.
Also, though my personal experience, sometimes the bat which felt light and picked up well suddenly feels a bit heavy and not as well balanced. I had this problem in a couple of matches when I had bowled 15 overs and had to bat at a No.3 fairly early on.
I had a Puma Vendetta which was 2.12 but picked up better than the 2.10 Fusion I got from James (as I took James' word for the pick-up and James has a slightly heavier frame than me). Can't blame James or Fusion for that.
so it all depends on the built of the person, their grip, middle position on the bat and maybe how you are feeling mentally and physically at that particular point of time.
As for having some regulation on commenting on the pick-up - that's the least bit of honesty one can expect from a seller. I have bought and sold bats on the forum with the understanding if the buyer does not like the pick-up he can return the bat.