In terms of penalties conceded the stats are:
Pocock 15
Gill 6
Hooper 3
And pilfers after Gill's "extra game" (that has him on less minutes than hooper) are:
Gill 15
Hooper 9
Pocock 8
As you said though, those stats don't tell the whole story as they don't include penalties won etc.
I wouldn't have a problem with either of Hooper or Gill being selected - I think they have both been dominant, match-turning players against quality opposition. Great battle.
I love debating about the value of good No7s. The funny thing is if we arent comparing internally then we are comparing internationally.
Whilst I love the old pilfer these days this isnt the most important aspect of the No7. Yes it creates a turnover opportunity and to use the basketball phrase the opportunity for a "Fast Break for the easy lay-up" which has been a trademark of the All Blacks in the Richie McCaw era.
The best aspect of the No7 is legally slowing the ball down to allow your defensive line to regroup and set up for the next phase without commiting huge numbers to the breakdown.
In this respect Gill has reigned supreme over the other noted 7s in the Aust Conference. This is as much a function of his talent as much of the system being used at the Reds. We have all noted the consistent low chop tackle over the Reds revival in the last few years.
As a result of the system differences between the teams no one is going to win this debate over who is better.
IMO 7s primary role is for defence and No8 is for attack and is best suited for linking with the backs. This then leaves the 6 to determine your philosophy of an attacking mindset or defensive mindset.