Was the idea of a regency for Aegon VI and Rhaenys ever really explored by the rebel faction? Rhaegar may have been more agreeable to a surrender if he knew his children would succeed him, and it was possible for him to take the black. Or did Robert just really want the throne that badly?

No, the idea was not explored, because the Rebel Alliance acclaimed Robert as their king – note the order of operations there – and once you’ve crossed that particular Rubicon, there is no alternative to removing House Targaryen altogether.

And I should emphasize, because I’ve responded to a few of these, but the political logics of a lot of these alternate scenarios are not sound. Even if Rhaegar was willing to take the black (unlikely), and Rhaegar’s supporters would accept that (unlikely), it’s not a good idea for the Rebel Alliance to support a regency for Aegon VI, because infant kings grow up and have excellent motives to revenge themselves against the people who overthrew their fathers.  

Are you going to make an Ant Man and the Wasp post?

Sure, I’ll do a short one:

  • fun chase movie. 
  • sense of humor from the first movie intact, so that’s good.
  • could have used a bit more object-based size changes: the salt shaker and the Pez dispenser were good, but they were in the trailers and there wasn’t much else.
  • liked the Inner Space-style Quantum Realm stuff. Michelle Pfeiffer as one of the Vuvalini was a cool take.
  • really liked that it ended with the main antagonist being reformed. Marvel hasn’t really done that before (don’t think Bucky quite counts.)
  • bit of a tonal shift in the post-credits. 

If most of the castles in Westeros are hundreds if not thousands of years old, does that mean that the art and craft of castle building has diminished in Westeros? Why aren’t there more new castles being built?

I don’t think that’s accurate. There are a handful of ancient famous castles that are that old – Winterfell, Casterly Rock, the Eyrie, etc. – which happen to be very old, and we spend a lot of time in and around them in ASOIAF.

But there’s a lot of more recent castles. And I would imagine castle-building is kept up through maintenance, repairs, improvements, etc.

Why is the North’s western shore so poorly defended against Ironborne? Seagard has its belltower and the Reach has watchtowers and the Shield Islands, but none such structures are ever mentioned for the North.

A couple reasons:

  1. The North’s population is more interior than coastal, so the shore is less important than it is in the Westerlands or the Riverlands or the Reach.
  2. The North had better defenses at various times – “Balon V Greyjoy,
    called Coldwind, destroyed the feeble fleets of the King in the North…We have had no strength at sea for hundreds of years, since Brandon the Burner put the torch to his father’s ships”
    – but have neglected them in recent centuries.
  3. Even without those defenses, the Ironborn don’t do well trying to hold the North, in part because “ironborn lack the discipline to stand a charge of armored horse.”

Did Robb plan to incorporate the Golden Tooth into his new realm?

Unlikely. Robb’s offer of peace describes his kingdom as incorporating:

“…all the Stark lands north of the Neck, and in addition the lands watered by the River Trident and its vassal streams, bounded by the Golden Tooth to the west and the Mountains of the Moon in the east.“

If Robb had seized the Golden Tooth in battle, it might have been a different story, but it doesn’t seem like he was making any claim on that particular castle