É suficiente, porém o nível do deck vai ser um pouco pior. O jogo é considerado difícil, então vai haver mais dificuldade no jogo.
Eu vou de new core set para experimentar e, caso goste, vou partir para expansões. Mas vou jogar no máximo em 2 players.
Mas sugiro esperar, o preço dos core sets antigos devem cair. Nos EUA, no jogo do AH, foi o que aconteceu. Mas vai depender do preço que vier.
- The original core set only had 1 or 2 copies of some cards, as well as 2 threat counters. Having enough cards for full deckbuilding depends on what you consider full deckbuilding. A deck can have up to 3 copies of the same card, and if multiple players share one or more spheres, then they might want a few of the same cards. If the players divide the spheres among them, then it's not a problem.
- See above for deckbuilding. The new core set includes 3 copies of all cards, as well as 4 threat counters.
- AFAIK, the only new cards in the new coreset is the campaign cards. Old + new core set will give you extra copies of all cards, with a few spares. The spares can be used to help multiple players wanting the same cards. The cards are mixable. Don't know about quality.
- All expansions include 3 copies of all player cards (excluding heroes). Buying another core set is really cost ineffective, even if there are good cards you may want an extra copy or two of. If you don't want spares of any cards, plus an extra set of all the encounter cards, I'd recommend selling the old core set and buy the new. Just keeping the old, and deal with the missing the player cards or proxying them (this is what I do), is also completely valid. Again, spares could be used if multiple players want to use the same cards.
- They have announced a few themed player deck expansions, centered around Dwarves, Gondor, Rohan, and Silvan, respectively. Old cycles will, I believe, also be repackaged into two deluxe sized expansions each. One for all the player cards in a cycle, and one for all the quests and encounters. I don't think any specific expansions of this type has been announced. None of them will include new cards, only repackaged old stuff, more beginner friendly.