Are Time Walking Cataclysm dungeons easier than they were originally? They most certainly are. They’ve had a number of nerfs, even a few post TW. We also have an expanded toolkit to deal with things. If you’re wearing a TWing set I’d imagine them to be even easier.
Are they easier than current Heroic dungeons? Despite all that no. I’d say they’re still slightly harder. If you don’t pay attention some mechanics will still one shot the unwary dps. Ask me how I know this. I’ll tell you anyway. The healer and I duo’d the last boss of Grim Batol from around 70% to 0.
Bumping the item level to 171 isn’t going to break anything. In fact it really won’t do much at all since you can grind anima to get 197 pieces now then world quest the rest. It might make a brand new 60 feel slightly better about running them though.