Let's analyze part 2 of the list :
Oracle : It's a fun and good card, but you can easily find better, so okay for the rank.
Village : "the best $3 card from the base set" : no wonder when you see the 3 other ones ^^. It's nice having it here, as a barrier between middle and good cards.
Watchtower : Powerful in some games, useless in others... but often nice to have, at least for the top-decking power, and it is still a drawer, so why not ?
Tunnel : THIS is the card I would have ranked much higher if I completed my vote. In fact : 2 VPs for $3 seems really, really strong ! And the reaction part ? Okay, in some boards it is pointless, and even a single spy doesn't make it relevant. But when there's only one card that lets you discard at least two cards at once (Secret Chamber/Young witch...), it becomes a tunnel rush, right ? And even without, as a cheap victory card, its pile is easy to empty !
Scheme : Really useful, I think it has its right place
Warehouse : we are going close to the top, so... yeah, there are not many drawers at $3, and this filter is most of the times nice. You know when to buy it... but I don't think it's that strong as sometimes you have not-so-bad cards in hand, and you draw not-so-better. I don't know how I should rank it.
Swindler : of course it is strong ! Of course it is unfair ! And when I play it I often say "sorry" but still buys more ! So no wonder this is here !
Steward : It is strong like chapel is strong, as being a fast trasher, and recyclable. But the two other effects make it worse than many other cards, according to me. So maybe wouldn't it be in my top 5.
Menagerie : This is the card that makes you expect your opponent to play militia/g.ship ... I love it in those games. But only in those, as is it too much luck-dependent otherwise. Plus it is weak with other good drawers, especially wharf that makes you draw two surprise cards. (and I remember having bad surprises from wharves)
Fishing villages : the best $3 for me, as it is a good buy in every game, far better than ambassador.
Masquerade : Very fun to play, but only in 2 players, and there are some games it isn't that interesting if you can trash by yourself. But if you've reducing handsize attacks, if you know before drawing two cards which one you'll pass... what's the matter ? No one ^^ deserves good rank, though !
Ambassador : Sorry to tell it, but I think it leads to boring games : "I return two estates, one gets to you" "thanks, here is another for you" etc... where are trashers, with those estates/coppers not disturbing anymore ? I'd rather buy steward/chapel !!! But it is truly a "strong" card...
I'm finished. I don't know if I will do those personal analyses for every ranking, but I was pretty goodly/badly surprised by some results for this.
See you soon !