Is it better to finish one dragon or raise several a little?

Finish one dragon rather than half-raising five. A dragon's strength doesn't come from its raw 🔥 number but from the combination of stars + leveled Habits + its Order.

Why concentrating wins:

• Habits weigh heavily (up to 5 stacked effects at level 5), and a ⭐ set Habit multiplies the dragon's ability.
• Stars unlock effect tiers (e.g. effects dormant until 6★/10★, like Crimson's 40% stun).
• A "complete" dragon is far stronger than its raw Power suggests — proof: Jagadrix, the lowest Power on the roster, stays the best thanks to its 10★.

So pick 2-3 pillar dragons (ideally including a good Center/Champion), push them all the way, and only then widen. All of that capital is permanent.