A couple of weeks ago, I bought The Dwarves: Big Box and I really enjoy the game. The original game has a rating of 6.9 which I find too low. I understand the rating as there is a good amount of luck with the dice rolling but it doesn't bother me for this game.

It's the "Big Box" so it combines the base game with all previously released expansions... and there is this on the front page of the rule book:
... There is also space for the 2 new Hero figures (available separately from your friendly neighborhood game store or online) in the Hero insert tray. ...
Aaaahhhhh! Releasing a "Big Box" and at the same time 2 new heroes. Yes those can also be used by those that have the original edition but seriously.
Yes, I gave into the fomo and ordered them from the pegasus.de web shop as they can't be found in any Belgium boardgames store. After shipping, I got 2 mini's and 2 player boards for the half the price of the big box.
Did I overpay? Absolutely. Do I regret it? Not a single second.
Having no regrets is always a plus! 🙂
I also got the Big Box because it had a few tidbits I didn't own already. It has been in limbo for months though (hopefully it won't come while I'm away as Iron Helm is set to do).
These missing heroes are really bad news (I mean, I got the big box to have the additional promos I was still missing). I'll have to do the same as you did, I guess. But at least I'm glad you enjoy the game - chances are, I will, as well!