It will be interesting to see how different the plot will be from the old G-series modules, and I'm looking forward to browsing this book to see how they handle the plot.
I haven't actually purchased any of the other adventure paths. I was curious about Princes of the Apocalypse but one of my players was already running that in a different group so I passed it by. Curse of Strahd also looks pretty good but I'm not looking to run a horror game at the moment... So Storm King's Thunder is really the first adventure to give me some sense of excited anticipation.
The second announcement was about Volo's Guide to Monsters.
What makes this book intriguing is that it appears it may borrow ideas from Monster Vault: Threats to the Nentir Vale.
During 4th Edition, Wizards second Monster Vault book took existing iconic monsters, and created "monster groups"... Basically, variants that differ from the typical iconic monster's stat block a bit to provide variety. As an example, you might get new stats for an Orc queen, a war chief, a shaman, Half Ogre and Half Troll variants, etc... Or an NPC faction with stat blocks for the different kinds of faction members (such as the Iron Circle, or Dythan's Legion), or even a special monster NPC, like Calastryx, a red dragon with 3 heads.
Threats to the Nentir Vale was one of the best books ever produced by Wizards of the Coast in that it wasn't just another Monster Manual. Each group entry had a backstory and campaign hooks that could be dropped right into your game as a named NPC or faction. Even though it was set in the Nentir Vale, the hooks were generic enough that any home game could use what was in the book with little modification.
I don't know for certain the Volo book will take a similar approach, but it would be excellent to have a similar book created for 5th Edition with campaign hooks and background fluff. It would be preferable if it were not limited to the Sword Coast, but expanded to other parts of the Realms. Better yet, it would hopefully be generic enough to use in any home game.
Will it present details on more monstrous PC races? Will it add Feats, Backgrounds or other player options? Hard to say. I actually like that Wizards has stayed away from creating too many player options that can be abused. Splat books almost always created unnecessary power creep in prior editions.
Outside of what appears in the official announcements, we don't have much information about what we might be getting, so all of this is just rampant speculation. However, I'm hopeful that Wizards is learning what has worked well in 5th Edition (as well as prior editions) and keeps improving their products using lessons learned from the past.