It has always depended solely on the official's judgement. It would be great to take that the official's judgment out of all games, but it is just not possible.
While that's a true statement, you're still missing the huge difference between
a) having a standard and looking at the replay to see if the standard was met, and
b) having no standard
The old rule was an example of "a," with the football move being one of the standards. There was no grey area in the requirement to be met. Judgment only entered into the
interpretation of that standard. We can disagree about whether Dez reached, but there's no disagreement that a reach was a football move under the old rule.
The new rule is "b" all the way. There is no standard for how long is long enough or for how upright is upright enough. It would be like leaving it up to officials' judgment whether an offense had gained the necessary yardage for a first down without having 10 yards as the standard. Imagine having to hold your breath waiting to find out if you made it on 4th down -- with no hash marks and no yard lines. Like gymnastics and figure skating.
Which of the following sentences is incomplete?
You know a team went far enough for the first down
because they moved the ball 10 yards.
You know a player held onto the ball long enough for a catch
because he got control with both feet down then made a football move.
You know a player was upright long enough for a catch
because...
How do you complete it? With "because the replay official said so?" That's subjectivity, and it's a step backwards. Maybe several steps.
The goal of the new rule was to relieve the replay official of accountability on this kind of play.