Will there be a dice pack. Right now it's possible to throw 4 dices and maybe in future we will need even more. I probably won't buy second core set but i could use extra dice.

Nothing has been announced. I wouldn't expect it at the moment. However, if abilities/command cards/or scenarios ever pushed it to the point where you were rolling a lot more dice, then maybe.

But as of now, I don't think re-rolling one die is too much of an issue.