It wouldn't be farming because if you customise the silders in '17 you're also customising the difficulty, so your difficulty setting would be "custom" if you change anything, not HoF, check it out in the main setting you can create your own difficulty and select it in-game as "custom" but it isn't available to select in MyCareer because people would abuse it.
I'm basically saying in MyCareer we should also be able to create out own difficulty but within the limits of the other 5 difficulties, the user might not like how easily the CPU hits shot on HoF but on the other end they might like how much of a challenge it is to score, be great for that person if they could just turn down the rate of which the CPU is making shots but keep the good defense, wouldn't it?
Difficulty and gameplay sliders were never tied together before, when upping the difficulty in the past the CPU's players would receive a rating boost but now on top of a rating boost they get juiced up sliders.