This is the third time I'm giving this game a try since 2013. The first time I bought the game I had one core and was getting stomped on every scenario. The second time I bought two cores and same results. I sold all my cards at that point.
Fast forward to a month ago - I had the itch and bought one core set after finding an excellent solo one core, one-handed deck by Jeff Hannes. I was finally able to see how the game is to be played out with a somewhat optimized deck. This revitalized my interest in the game. I went back to trying to build my own decks and now I'm banging my head on the wall again.
The issue I think I'm running into is that there are only a few viable hero combinations that work out of the core. Eowyn seems to be an auto-include if you want to have any success with questing. I've tried not to spoil too much but I hope that she at least has an equal in questing in future packs. Was trying to fit Gimli in since he seems to be THE combat god, but his high threat makes it difficult to include and also at that point you're down to deciding between Lore and Leadership for your third hero which both seem equally important.
From what I read the first cycle is difficult but the game really opens up with Khaza-Dum. Is that my next optimal purchase after one core? Will I be able to build better decks with that cycle? The heroes feel very limited right now and therefore so do my options. I'm sure a lot of that is my experience even though I'm a heavy card player (Netrunner, Arkham Horror LCG, etc).