In 1.9, armor was nerfed such that higher-damage attacks pierce armor better than low-damage attacks. Specifically, for every 1 damage point a single attack does, 2% of the armor protection is ignored. Toughness was added in 1.9.2 to counteract this nerf, and it only appears naturally on diamond armor. Full diamond armor has enough toughness to reduce armor-piercing to only -1% protection per damage point. If a person were given a very high value of armor toughness through commands, then armor would behave like 1.8 armor.
Sure Sharpness was nerfed because it was stupidly OP in 1.8, just like Prot. In 1.9, you do 1.08 dmg with Sharp V diamond sword against full Prot IV diamond armor, and 1.628 damage if it's a crit. In 1.8, you do .57 or .73 if crit in the same gear scenario.
The healing system isn't a joke, it's a nice balance between beta food and 1.8 food. Chugging steak is still not as powerful as chugging normal gapples, and you can't exactly do that and survive even in 1.8 can you? On top of that, you can't eat steak/garrots constantly due to needing to be hungry, and you'd be out-damaged by someone (yes, even in NoDebuff) if you tried to chug steak. Healing pots are still a much better way to heal.
Your complaint was literally that bow was too strong, but now it's okay for UHC?