My up-do-date ranking of Landmark Impact (differs substantially from what I submitted):
21. Baths
20. Basilica
19. Labyrinth
18. Obelisk
17. Palace
16. Arena
15. Collonade
14. Aqueduct
13. Mountain Pass
12. Defiled Shrine
11. Battlefield
10. Fountain
9. Tower
8. Triumphal Arch
7. Bandit Fort
6. Orchard
5. Tomb
4. Wall
3. Museum
2. Keep
1. Wolf Den
Notable differences from community rankings (not just the largest numerical difference):
Wolf DenCommunity Rank: 6
Personal Rank: 1
The thing about Wolf Den is: it
always affects my strategy. It's something I think about on the very first turn and throughout the game. -3 VP is a big deal, and it is rare for a unique card to be worth that kind of VP hit (it can happen, of course). No other landmark so consistently affects my strategy. Though, Keep and Museum almost always affect my strategy from midgame and beyond, and they put more VP on the line, so I could see an argument for Wolf Den at #3 - but no lower.
WallCommunity Rank: 1
Personal Rank: 4
Not a huge difference, but a notable one. Wall does make me carefully consider my strategy from turn 1. But unlike Wolf Den, Museum, and Keep: Wall doesn't always affect my strategy. There are boards where there's not much you can do to play around Wall, and so it ends up having a minor impact. There are other games where Wall can give you -10+ VP more than your opponent, but the Alt VP is powerful enough to overcome it.
FountainCommunity Rank: 4
Personal Rank: 10
It's very rare for Fountain to be worth pursuing when there's a good way to trash Coppers, and that's a majority of kingdoms. On the minority of kingdoms where there is no (good) way to trash Coppers, Fountain is a big deal, and there's some interesting strategy to figure out when to add the additional 5-VP Coppers to the deck.
TombCommunity Rank: 12
Personal Rank: 5
Sometimes Tomb has no effect on the kingdom. Sometimes Tomb has a modest effect of nudging both players towards a thin engine with weak payload over the alternative. But a surprisingly large portion of the time Tomb enables interesting strategies where trashing cards is a large portion of the payload. Maybe I have Tomb slightly overrated, but these kingdoms really stick out in my mind.
ObeliskCommunity Rank: 10
Personal Rank: 18
drsteelhammer said it best: "I am wrong and so are we all, apparently. Buying bad cards for VP doesn't make the cards better." It's shocking how little impact Obelisk usually makes. If Obelisk is on a good non-terminal, winning the split was probably important absent Obelisk - with Obelisk it's slightly more valuable. If it's on a decent non-terminal, maybe it encourages one or both players to buy them before greening on boards with weak payload. If it's on a good or decent terminal, it replaces maybe one Duchy buy (in games where that matters). And if it's on a weak card, Obelisk simply doesn't matter.