The trailer is fantastic! The hype is awesome. Well done CDPR and Gwent Team!
My thoughts about the cards and keywords:
NR:
With Shield NR will become a formidable faction. I am sure there will be cards which give shield to other cards (some cards may give shield to more than one units too, and I can guess that some of the existing engines may come with shield). The new leader for NR will give shield to a unit and may have 1 charge per round making Foltest redundant (unless the new leader also has less provisions).
ST:
Poison seems powerful. Too powerful that it will have some very simple counter, like boosting a unit will remove the poison (or something like that). If there is a simple counter to poison, then as usual ST will have the most pathetic new addition. If not, ST will be strong. Harmony is a joke. Unless all the existing golds which need 5 elves or 5 dwarves to break-even are changed, there wont be any good card to support the Harmony. Lets see.
MO:
If bleeding can be stopped by killing the unit which gave bleeding or boosting the bleeding unit (or something cheap), then it is a fair mechanics. Otherwise, it is just too powerful. The card that was introduced breaks even on deploy and can get +1 guaranteed or +3, which seems insane. But I hope there is a simple answer for bleeding.
SK:
Yes, why not? +3 easily. Even if Bloodthirst 3 is not achieved, +3 is still too good. But at this point, I am not shocked to see MO and SK gets more powerful cards than the rest of the factions.
I am sure NG will get amazing cards too.