[Nate the Great]

1. Why do Vulcans have art?

Because a person can't meditate or study lab equipment all day. Because creating art exercises the mind. Because becoming fully logical takes time, and this art could be really old. Tradition.

2. Why does Spock love the lyre?

"Love" may be a strong word. Because creating music exercises the mind. Because everybody needs to listen to music every once in awhile.

3. Why is the HOAT so glorious? Why the ornate robes? Etc.

Because ancient Vulcans were more like Romulans and actually had emotions. You can't attribute logic to anything more than (say) a thousand years old. It takes time to fully purge emotion.

Replacing key structural members to increase size and replacing key structural members to decrease size are different propositions. And at least to increase a ship's size you can simply technobabble-bolt on more bits of beam.

Every piece of a starship's infrastructure is based around supporting a crew of X people traveling at Warp Y assuming the warp core has power capacity of Z. This guy is suggesting that Z proved unstable, so that had to be shrunk, requiring X and Y to be shrunk as well. This is drastically altering the fundamental formulas that dictate the design strategy of a ship.

Before any structure can be built we must know what forces will be applied to it. We then magnify (for safety) and combine (for simplicity of design) the forces to find out what each piece of the puzzle could be subjected to. Lowering the power output of the engines and the maximum speed of the ship reduces the magnitude of the forces acting upon each structural member. Hence a slower ship with a weaker engine could handle a larger infrastructure size. If the new "defit" engine is THAT much weaker that the ship STILL has to be shrunk, shrinking the ship enough to move is just creating an engineering disaster.