Reverting all the player overpowering changes they did would be a proper way of making the game harder. Not just for honor mode but regular harder modes too.
Shove distances, free spell memorization, potion throwing, amped up Help action, jump distances, haste buffs, unrestricted multiclassing, unrestricted scroll use, easy vulnerabilities like "Wet" etc.etc.
Unlimited Long Rest is the worst offender rules wise but also the hardest one to fix. Camp supplies don't really do anything except add frustration if you run out so they'd have to go much further than that.
Then there's all the environment cheese, stealth cheese and kiting the AI with Dashes from a buffed up action economy.
Needs a lot of work still.
