DR-MR-AMR players - Defenders or attackers ?

[Toxcatl]

I really don't see any difference in balanced skills and increasing (relative to position) skills.

Because you are comparing different players, and skills is not the only thing that affects performance.
None of these players is minimaxed, by the way, all the skills are balanced on your screenshots.
It may be a placebo, but I've never have my team being that effective like now, since I started to concentrate on 2-3 skills (mostly Fitness and Speed) instead of doing same old Press the play.