The core set is as advertised: a core set. While I really, REALLY think it could have used 40 card decks instead of 30 and allowed for single sphere legal decks out of the gate, that wasn't what they decided to do. I would, however, recommend a second core set. Online you can get it for 20-something dollars and turning all those 2x cards into 3x is huge, not to mention giving you a couple of the powerful uniques. 3x is certainly overkill as there are only a few 1x cards, and even fewer that are worth including, but I've found the second to be worth it. Your mileage may vary.
On the plus side, there is some deckbuilding fun to be had with 2 sets combining spheres. Though there is certainly a resource disadvantage unless you are using Leadership (who has access to the uber powerful Steward of Gondor), it at least allows you to have some fun and start testing the waters.
The bad thing is we're not going to be able to have any major deck building for several months. I'm a little uneasy about the majority of each expansion being new quests...maybe every other expansion, but every single one? I would prefer more deck variety to more quest variety, and I'm really hoping they change their strategy. They have already said there will only be 9 new cards per expansion, and spread out among the spheres this is, on average, 2 cards per sphere, some of them bound to be unique. That's 1 expansion until a single sphere is playable using all of their cards, but many expansions before we have any real options. Oh well, after this arc they might re-examine their strategy.