Interesting. Seeing a lot of power creep here...
Colonialism and Gleaners are better resource get cards then those currently existing... compare Gleaners with Caravan or Saint's Day, for example. Ah, well; standard comment about crappy 0-cost cards and Danai Present.
New Development raises the bar on towerup cards; being more effective and expensive then any other existing one. Inefficient if played poorly; as with most such things.
Shrine is significantly better then Basic Wall, as there are a lot more positions it can be used in, AND it has an incidental +Gems effect.
Perfect Shot doesn't exactly 'raise the bar' on direct attack, given the existence of Elven Archers... but it is a lot easier. It's also another common that does this, and it uses a different element, so it intensifies the strategy.
Death Prophet makes 'mutual facility destruction' an easier strategy to implement. Having tried it myself on a number of occasions, I don't find it a good strategy, but your mileage may vary.
Elementalist brings the much asked-for Unliving nerf. Not that I expect to see it that often; being a specific countermeasure, it's one of the cards that people won't usually put in their deck unless they're fighting someone specific. But now that it exists, it should silence some of that inane nerflust, so I'm in favor.
Valley of Thousand Rivers / Revenge of the Fallen... wow. That's something. They look broken at first glance, because they're improbably cheap. The random probably isn't sufficient drawback to deprive them of awesome. Trick is, I can't see them being much less awesome if they had a more significant cost, because of how greatly they're underpriced compared to other cards doing the same thing. Of the two, Valley is probably less broken, because there are more cards that could go into it, and because Facility+ is typically cheaper then Facility-. I'd recommend adding Burning and Destruction to Revenge; that evens the two out. Not sure if that makes them balanced against everything else, but it'd be a start.
I like Darkforge, because it intensifies my existing strategy. Alliance should always have something it can do with heaps of recruits, thanks to Mountain Sentry... this just represents another way of doing that. Recruits x20 is pretty impressive... and easily possible, given a bit of planning. If tokens is also being implemented, the planning is more obvious.
More thoughts later.