Asteroids don't have gravity, forces you to figure out radiation shielding (which, granted, is probably as simple as digging into the asteroid), and requires you to keep a pressured environment with a 1-atmosphere difference.

I wish the article had expanded more on the idea of removing a lot of the atmosphere. I wonder if an asteroid could be sent in such a way that it tears through the atmosphere and rips a lot out into space. The rock would pass through and back out into space.

Venus is almost as big as Earth. Any asteroid is much, much smaller. So the amount of atmosphere you would remove would almost certainly be minute.

The ~50-megaton Tsar-Bomba reputedly "lifted" the atmosphere above its mushroom cloud off the Earth and into space. The Russians allegedly had or have a 100-megaton version which could presumably perform more "heavy lifting". There are probably more scientifically-minded readers here who possess a formula which will show the ridiculous number of Tsar-Bombas needed to make Venus safe for Humanity.

I've read that comets could be slammed into Venus, modifying its rotation, and somehow reducing or eliminating the runaway greenhouse effect. Of course, if mankind is at the point of being comfortable terraforming with comets, it may make more sense to point them toward the desert planet Mars.

"There are probably more scientifically-minded readers here who possess a formula which will show the ridiculous number of Tsar-Bombas needed to make Venus safe for Humanity."

Not to mention the nuclear fallout that would drift for a long time all around in the atmosphere - basically anything but "safe for Humanity".

Very unlikely; imagine swinging a pendulum through a water tank. Gravity pulls things down, not up; you're more likely to add some vaporized asteroid to Venus' atmosphere than have it "rip a lot out".

I'm trying to think of some kind of space-elevator-siphon, but there's no getting around the fact that, unless you want to expend energy to pump it, you have to have an equal amount of mass coming down as is going up.

I don't like the idea of provoking the loss of mass of some colonizable planet that already has less gravity than it would be natural for us. A better solution would be to trap as much of that atmospheric mass in solid aggregation state somewhere on its ground. Our planet had a lot of atmospheric carbon too, which is now trapped mainly as coal or other kind of fossil fuels.