So, I know this is too late, but I would like to point out that people (including the author of the card) are looking at Observatory in a way that I think is wrong. They look at it and see it does something better the more expensive the card you trash, they peg it as 'oh, it's a T4B card', and then the evaluate it solely as a T4B card (how likely is this to make me want to trash expensive stuff?) as opposed to just as a plain card. I mean, the thing is, you don't want to trash expensive stuff to it really, it's just a worse apprentice. Fine. But it's going to be cheaper than apprentice. Like, compare it to forager - it doesn't give you money, but forager reasonably often doesn't do that either, early on, and this can draw you a card. Forget the filtering, it draws you cards reasonably often. Indeed, the biggest knock on it to me is that there is this sort of weird feeling where there's a huge jump from trashing a freebie to a 1-cost, because you get a card. But just as a non-terminal trasher which occasionally does a little more, it must be a pretty decent card.
I feel like people did the same thing with my card last week - stronghold (gave you 3 spoils, VP per 2 spoils in deck at game-end, cost 6). People see, "oh, it's alt-VP", then judge it only on its VP-gaining abilities "You have to hoard spoils in order to make it worth anything, hoarding spoils gives you lots of dead cards, that's bad, the card is terrible." I mean, sure, but nobody is forcing you to play it this way. You can spend those spoils - and even gain them back again later. And here, same thing, nobody is forcing you to trash expensive cards, just go ahead and trash your coppers.
Recycle, the thing there is that it does a lot of stuff for you at 5, as a very strong T4B, and well maybe that's fine, but I am worried about the situation where you go Turn A: trash (gold-or-even-province), gain province. Turn A+1: Trash province-into-province. Pile trashing provinces isn't necessarily bad, but doing it so much and directly is pretty dangerous. Honestly, I think this is why rebuild feels so un-fun, it pile trashes your main victory cards, and makes it very very hard to come back from behind. So that is my big worry, apart from it just being a bit too powerful at the moment.