Well, I'm nowhere near player skill level to survive all these rules, and generally don't like them, and like cheese, so perhabs I shouldn't speak in this thread, but I still think I have something constructive to say.
I don't wall off, but use traps instead. Still, completly walling off would actually increase the game difficulty for me. I need wood and water (before I make invader proof water intake with fortifications and floodgates, plus a big inside tree farm, but thats beside the point). I also want migrants, and to trade with caravans.
Waterfalls would still be a challenge *IF* made with actual plumbing (recycling water or disposing of it), not mist generators powered by water reactors. Actually I wouldn't sneer at someone who managed to put a waterfall or a well in hundreds of bedrooms, if they were made with actual plumbing taking up whole Z-levels.
Oh, and one last thing about walling off. There is the "raised bridge at the edge of the map" exploit that in combination with walls makes an almoust safe path for traders. That is just to "wrong" for my tastes (and I do enjoy magma workshops, DR training, and water reactors). I even think Toady wrote sth about "removing remaining edge of map exploits". Anyway you might want to write that explicitly in OP.
Trash compression should be at least borderline. There will inevitably be some things, that you want to get rid of. I don't mean stone, but goblin trash, low quality furniture, and such. They can be traded to caravans or dissolved in magma, but DAS is a viable alternative. What you might want to disallow instead is abusing quantum stockpiles, especially putting hundreds of raw materials right next to a workhsop.
Another reasonable limit to DAS would be: It is ok to destroy trash, but not living beings, and definietly not invaders (Elves are not trash, btw).
About big dining rooms, prepared meals and good booze:
Pretty much everyone uses these, and I disagree with this constraint. Well, maybe a dining room totally pimped out with jewel encrusted furniture worth 2k+ each is an overkill, but other than that dining rooms are pretty integral part of any fort. Plus when set as a meeting zone, it may somewhat increase potential for tantrum spirals.
Booze is simply a necessity, and brewers *will* skill up. The only reasonable constraint here would be "only use chaep stuff, like plump helmets to make alcohol", but even that is a stretch IMO.
Prepared meals, especially after cooks skill up are quite ridiculously expensive, and they spoil slower and save barrels. Maybe consider allowing 2 ingredient meals only? They are still somewhat "not hardcore", but at least less cheesy than lavish meals.
What about adding "Do not manipulate strange moods" Especially do not have everyone make one weapon and one armor item, and don't keep small steel stockpiles close to metal workshops. A mooded dwarf can make anything out of anything he likes.
Your list also lacks "no savescumming", just keep playing.
What about "don't kill pets" "don't kill dwarfs" "don't kill nobles" "don't kill caravans (wall maybe elfs if you really want to)"?
I had one last thing to add, but I forgot.
EDIT: I remember now. Don't tinker with creature speed. Especially don't set Dwarf speed to 0 or 1 or something like that.
Oh, and change the title of the thread to sth. like "Common ground for a challenging playstyle for veterans", or people *will* complain, that you call them dishonorable.