Wow, lots of replies.
Here we go with the responses...
Genearl stuff:
I feel the ranking is a bit misleading because it mixes rank with category, which just has to be flawed by some degree.
Yeah, I know it's flawed, but I really did it for simplicity. They are loose rankings and that's why I didn't put a number before each card. But I think it's useful this way. If you're teaching someone what are the important things to look for in an opening, it's easier to think: amb/masq, curse, good trash, attack, vps, other trash) than to think (amb, masq, sea hag, remake, young witch, swindler, salvager, militia, steward...) or something. I had to make some concessions (as I mentioned with steward) for the sake of the article, but I think it makes for a better article arranged in this way.
I don't know why you restricted it to terminals, either - you could honestly just say cards overall, and I don't think you've missed any... though I might be forgetting something I guess.
I decided to restrict to terminals because you usually only buy one terminal. Non-terminals, like chapel, can be bought along with one of these cards. Comparing swindler to tournament, for example, is not important, since you can just buy both.
More specific:
You can get a feel for the opening terminals by looking at the Councilroom stats for a Silver/x opening:
http://councilroom.com/openings?card=Silver
So, your list is not bad. Basically it's (if you want to categorize):
1. Premium trashers
2. Mean attacks
3. Good trashers / VP token gainers
4. Weaker attacks / Carddraws / Weaker trashers
5. The rest (stuff like Bridge, Baron etc.)
A slightly different picture (not sure if it's better -- it includes the possibility of not pairing with silver, but doesn't account for level) can perhaps be gained from looking at win rate vs turn for turn 1-2. You'd think the rankings would be the same for both, but they're not, and that just goes to show you how noisy any esimation of rankings from this data is. But there you almost do actually see the first 3 tiers with significant gaps in between -- ambassador/masquerade, sea hag/young witch, remake/salvager. Then swindler just ahead of a muddled mess including militia, bishop, cutpurse, monument, envoy, steward and moneylender with differing order depending on if you look at turn 1 or 2. Then island.
More specifics:
I think Moneylender belongs up with Salvager and Remake in a "trash for benefit" tier, and I might in fact even put one or more of those cards above the curse attacks, but other than that, I agree with all of this.
I'm not a big fan of moneylender. I really like the effect of loan, since it's a non-terminal $3 card, but I never really consider getting moneylender ahead of an attack, while that consideration does exist with remake and salvager. That distinction prevents it from joining them.
Steward is an elite opening card, I promise you Definitely worthy of mention ahead of Young Witch (which I'd put much further down the list in general) as well as Salvager and Remake.
As I mentioned, the problem with the structure is that I can't just throw steward in the middle of the attack tier or something. It's either up with remake and salvager or down with moneylender. I went with down with moneylender. I guess you'd say up with remake, and I'm not sure I can argue with that. In fact, I considered it, and added in island to the bottom just so moneylender wouldn't be lonely, but I ultimately decided to just drop steward. Choosing between steward's trashing and an attack depends on the mid-game strategy you're going for as well as the non-terminal you go for, but I think attacking is generally stronger. If you get militia'd on your non-steward turn, you're going to have a hard time buying anything for a while...
Islands are not really great openers, promising a slow improvement for most decks. It's quite rare that you'd buy them as an opening card and they progress your deck better than any other Dominion card could do. The times when they do excel are probably just as rare as the occasions when a watchtower, workshop, woodcutter, conspirator, coppersmith, treasure map, moat, embargo, bridge, courtyard (and so on) are perfect for a deck.
I'd actually suggest that the pirate ship should be included in the strong openings unless multi player games are excluded. Although it seems situational the same can possibly be said of bishops, salvagers, and moneylenders.
Island is not a great opener. It's last on this list. I don't think it ever really "excels", but it's generally better than all the cards you list, which for the most part require specific strategies that involve the particular card. The point of including island is that in the absence of any really good openings, being ahead a couple points is great unless your opponent can find a way to buy an island along with a province. Otherwise, they eventually have to buy an island or duchy to catch up. And since you bought yours earlier and used it for a trash, you're ahead.
Pirate ship is a strategy, not a general opening.
You're drastically underrating monument, like everybody does.
Young Witch is about impossible to rank without knowing the bane. It's entirely not worth it with a good bane, probably not worth it with even a decent bane.
Ambassador (in 2-player) is generally a bit stronger than chapel. So is masq. Remake is barely, barely below them.
Salvager certainly isn't a tier 3. Actually, it might be the worst opener on the list.
But fairly good overall.
Where would you put monument?
Young witch's goodness definitely depends on the bane, but it goes with sea hag because of the structure of the article. Without a good bane, it's definitely miles ahead of the other attacks, so I feel it's fair to put it up there.
Salvager has a lot of complaints, so I guess it gets its own section in my responses...
Salvager stuff:
I'm very dubious that Salvager is a great opening. It's a trash-for-no-benefit for Coppers, and it's a "trash for a one-use Silver" for Estates. It's a terminal, and it won't get you to $5 unless you draw it with exactly 3 Coppers + 1 Estate, and won't get you to $6 with any combination of starting cards.
Salvager is a good card, don't get me wrong, but its utility doesn't come out until later in the game when you can either draw and play it more consistently, or where it's trashing higher-value cards.
Salvager buys like silver while trashing a copper about 2/3 of the time. This is a really good effect. The other third of the time it does just trash a copper, which is not good, but not the worst thing in the world, and you still keep the salvager, which you're going to want eventually anyway. My feeling is that you might as well buy it up front.
Remodel and salvager are mostly as useful as each other with different applications. It might be harder to misplay a salvager as you can usually salvage something.
I think salavager is *worlds* ahead of remodel. Remodel requires you to have a strategy that relies heavily on $3-$3 cards, since you're often turning an estate into a $4 and buying a $3. Salvager goes well into any strategy, as the money gets added into one big buy.
I should also mention that salvager is not ahead of remake because I think it's better. I swapped the order because I wanted to mention it in the remake blurb. I do, however, think it's on the same rough level. It's a trashing card I'd generally prefer over non-curse attacks. Given both are available, remake is usually going to be the choice, and I guess I should mention that...
I'll update the article with some of these considerations soon.