Balderdash.
Switching out of a physical attacker that can kill you is not a bad idea - it's like the exact opposite of a bad idea. That's like saying that switching Chansey out of a Close Combat from Terrakion is a bad idea - it's not; it's going to kill you, why wouldn't you want to switch out? The same logic applies to Goodra; run away from physical attackers that you cannot handle. This is why you have five other team members: Goodra is not a one-dragon answer to everything.
The second half of your statement is also incorrect: there is a reason that Life Orb Greninja's Ice Beam has been listed repeatedly in this thread, and the reason being that Goodra's Super-Effective coverage makes it so that there are few safe switch-ins against competent players. One of the most wonderful things about Pokemon is playing the prediction game, and all of the common switch-ins to Goodra risk taking massive damage by switching into the wrong attack. Azumarill, Togekiss, and Heatran all fold to the right guess - Heatran especially because he relies on Goodra using Draco Meteor in order to force him out (because the most Heatran can do is use Toxic), and the only way he's avoiding being 2HKO'd by Hidden Power [Ground] or Focus Blast is from that self-inflicted -2. Opponent's that recognize this aspect of Goodra are going to weigh the pros and cons of switching and, sometimes, losing your Greninja or Starmie (and stripping Goodra of ~45% of his health) is worth it if that means you can bring in your Choice Scarf Terrakion and punch a hole through your opponent's team with Close Combat. Of course, the wrong prediction on the side of the Goodra player will result in it being forced out, but the point in mentioning any of this anyways was to say that it's a coin toss and Goodra is a dangerous Pokemon and that Goodra is totally going to be taking Special assaults if it means the opponent can guarantee the safety of another Pokemon.
In addition to that, what do you think Goodra is switching into most of the time? It definitely isn't physically oriented Pokemon that are going to nearly kill him with their high base power, STAB attacks. No, Goodra is switching in to Pokemon that he can force out - Specially oriented Pokemon that will deal nearly no damage and force the opponent to weigh the pros and cons of losing that Pokemon or the switch-in to the wrong prediction.
Finally, why are you investing in Goodra's Defense Stat if you're asserting that even after max investment and a positive nature he still struggles sponge neutral, STAB assaults? Wouldn't that only strengthen the argument that Goodra is better off geared more towards what is being discussed, like the sets I have posted?
Basically this, besides, it leaves a Physical Attacker prone to switch out after it is attacked anyways thanks to Gooey! pokelover32, have you even tested Goodra?