I wasn't necessarily suggesting
Kjbert was comparing GZ's and Rocha's playing style, however I do think it's a tough ask to compare similarities in "impact" when discussing such vastly different players.
I tried using the NFL comparison of a LB to a free safety in the sense that if you had a bad pass defense in 20xx and brought in a run of the mill LB whose strength lay in pass coverage and he was deemed to have a positive "impact" on improving the team's defense, it would then be unfair to hold the new free safety (who was acquired the following off-season) to the same "standard" of impact; especially under a new head coach and presumably a somewhat different system.
Shwafta mentioned GZ and Rocha would be in competition to not win the Ben Sweat award. Maybe I'm being pedantic but again I'm not sure you can compare Rocha or Gideon to Ben. All three players are asked to do completely different things.
The reason why I think it's "dangerous" (likely hyperbolic) stems from my believe that you can't really compare the impact that player A will bring over player B because their games are so different.
What if at the conclusion of the 2020 season we end up with the same exact point total, W/L/D record and goal differential as last year (including the same type of postseason exit), and after completing a detailed analysis we come to find that the team scored more goals (but surrendered more goals) when GZ was playing and scored fewer goals (but also surrendered fewer goals) when Rocha was playing (assuming of course that they started/subbed and played in the same amount of minutes)? How do you measure impact?
I actually think Rocha is much more Ben than GZ is but I'm not about to make that comparison because they play entirely different positions and for me they're different players.
I don't want GZ to be considered a flop or less impactful because he's compared to Rocha for better or for worse. Maybe Rocha helps us preserve one win by way of a dangerous tackle in our own box which should have been a penalty but wasn't called. Maybe GZ helps us win 3 games because he was supremely efficient in his passing and tidy in possession, minimizing the opponents scoring opportunities and maximizing ours. You can easily quantify Rocha's game saving tackle, but it is much harder to quantify GZ's impact on the offense as a whole.