Is there any way to see all the Allies cards in the set like you can other sets?
I have the Allies preview on and I get a couple of cards each game, but I seem to be getting pretty much the same cards each game. I would like to see all of them.
No, the set is not released yet. Currently you can play with the cards previewed by Donald X, you can find the previews in threads created here:
http://forum.dominionstrategy.com/index.php?board=1.0
There will be another preview every weekday this week. It is unlikely that all the cards in the set will be previewed, so for the rest you'll have to wait for the release.
At the time of writing there is no set release date, but mid-March very likely.
I am not seeing any preview cards in my auto match games, at least not since Feb 28. Am I doing something wrong?
Rated games don't have them. If you only choose "Previews Yes" or "Preview vs Bot" you should get them (for the next 15 hours).