Overall, I was rather underwhelmed by Dragon Magic, but it does have one incredibly powerful new sorcerer spell -- Arcane Spellsurge. It lasts for 1 round/level, and it basically gives free quickening to all spells for the duration. Specifically, any spell with a casting time of one standard action becomes a swift action, and any spell with a casting time of a full-round action [1] becomes a standard action. So a sorcerer can cast Arcane Spellsurge spell and then start firing off two spells per round (one metamagic, one not) for the duration. You'd even be able to cast an extra spell (as a swift action) on the same round you cast Arcane Spellsurge.
The reason I keep referring to it as a sorcerer spell isn't that it's sorcerer only. It is Sor/Wiz (and even Wu Jen), but wizards don't have any good way to cast spells that take a full-round action, so it's far less useful for them.
[1] WotC appears to have fallen victim to their own confusing wording here. The table says that a normal casting time of "1 full round" becomes 1 standard action. However, the text explicitly mentions that a sorcerer would be able to cast a metamagic spell as a standard action. My best guess is that casting times of either 1 full-round action or 1 full round become 1 standard action.
The reason I keep referring to it as a sorcerer spell isn't that it's sorcerer only. It is Sor/Wiz (and even Wu Jen), but wizards don't have any good way to cast spells that take a full-round action, so it's far less useful for them.
[1] WotC appears to have fallen victim to their own confusing wording here. The table says that a normal casting time of "1 full round" becomes 1 standard action. However, the text explicitly mentions that a sorcerer would be able to cast a metamagic spell as a standard action. My best guess is that casting times of either 1 full-round action or 1 full round become 1 standard action.