Yes

Edit: This is now implemented in Alpha/Beta 0.15, along with Ctrl+C, Ctrl+V and Ctrl+X. Also works cross-shader, so you can close SF safely while keeping your clipboard content :)

Ah, that's a good point, perhaps it should be greyed out :) Will polish this behaviour in the coming beta

It's not really broken, but it's interpolating per-vertex rather than calculating per-fragment, which will look bad on low-poly objects. There should be a per-fragment option. I'm renaming this thread and switching it to a feature request rather than a bug :)

If you want extra spec, just multiply your spec with 2 or higher. Shaders aren't limited to a 0-1 range :)

Texture lookups are the amount of times you sample a texture, not now many textures you have. You're essentially sampling a single texture twice in one, and once in the other :)

Will fix this!

In the meantime, append a Value of 0 after the Sin node, making it a three-component color should make it multiply with the texture correctly

Edit: You can now do operations with different component counts in 0.15 :)