Why not make EVERYTHING more challenging?
They should. By removing aim assist. Try using SMGs/ARs with the wii remote and do it for a few months. Not "easy mode" then. You won't. And they won't remove aim assist either. (Not starting another aim assist debate. It's just more difficult to use the wii remote with those guns.)
Quick Scoping is cheap. Im not saying it takes no skill to do well, but every other weapon in the game has characteristics that are in line with what you would expect. Shotguns are ok to kill in one shot at close range, but with quick scoping you get both short and long range one kill shots. The problem has been that the map designs have sucked for hard scoping. I hated snipers in Goldeneye on Wii, but they were exactly what I though snipers should be. Find a spot to snipe and try to stay hidden, but there were plenty of spots to snipe from. I have no issue with hard scopers, but quick scoping wouldnt work without ads snap and aim assist. Hopefully Ghost has more open maps than the previous two COD's, the close quarter combat has made SMG's and work a little to well. SMG's in Black Ops were about right, but in MW3 and Black Ops 2 they were a little to powerful for how cluttered the maps were.
I basically did that for a whole year on MW3 Wii and still held a 2 KD. The CCP assist there was a borderline placebo effect.
Stop assuming just because you use your motion controls without assist that it's the same as DA. Dual analogs need a certain degree of assist for FPS games. The Wiimote doesn't because it has more fluent aim/freedom. Take your own advice and try DA without assist for a month. You'll see your scores noticeably drop in comparison to the Wiimote.
Even without assist, COD ARs/SMGs are very simplified and easy to use in comparison to other FPS games. They're all high damage, fast firing and barely have any meaningful recoil. Even on high recoil ones like the Scar it's just a matter of pushing your aim down to compensate. No real strategy or anything to differentiate skilled players and noobs. Just point and shoot. No focusing on headshots like Halo or controlling shots/bursting like Counter Strike/Rainbow Six, no consequences for mindlessly spraying, ETC.