Of course you can take out those classes first, but this means you're taking out every class (except scout because goomba's are useless now). That doesn't change much now. You can try to counter the classes by moving in an odd way, but classes also counter that. Snipers counter jumping hales, demoknights counter zigzagging hales ... Eventually you can't counter everyone
If sniper got nerfed so he wouldn't be able to place himself in a tough to reach spot while still deal massive damage, snipers counter would be weakened so he needs to position himself better. He could either be a heavy hitter or a jump counter. (of course can still remove hales in-air momentum while staying on the ground but it would be a lot harder).
In my eyes is high damage output+low skill requirements+low risk OP. Sniper doesn't require that much skill and when placed in a proper area can deal amazing damage while being low risk. Changing the bushwaka means that he'd either have low skill+low risk but low damage output or high damage output+low skill but high risk.
As for this, the cozy camper is definitely not necessary. To get up high would cost a lot of health, but assuming you found a good spot, you won't get down. The cozy camper is from what I know only used for escaping, since your health regains too slow for you to bushwaka jump another time in the same 'jump session'.
Like a year ago when I still had a proper pc I had some minor annoyance with snipers since their always on extremely hard to reach spots. And damn it I used to be a great hale.