It's cool that its your opinion, but Im pretty sure not a single athlete in the roster, from today or yesteryear, would agree with such a bizarre statement, or would prefer to fight Rigg. Not even Jonny himself, there is a reason why the guy went through tough weight cuts and contained himself from his biggest pleasure in life (food): to avoid contenders as Romero.
Regardless, the bias is clear enough when you label GSP as "the king of not making mistakes"....apart from the fact that I'd not put such label on anybody LOL, much less on someone who isnt undefeated, particularly in GSP's case his striking defense certainly had flaws and as a matter of fact he got hit clean and hard by profficient strikers as BJ and Condit, and not as profficient as Hendricks or Serra.
Well, I could say that your bias against GSP clouds your view as well, but instead, let me explain further.
At the time Hendricks fought GSP, he was at the very peak of his career.
He used his wrestling (more than Romero), he had KO Power (as much as Romero) and let us not forget that he did not gas (remember stool gate?) That was about that time, on a 3 rounds fight while we can say he arguably won against GSP on a 5 rounds fight! Romero would have had a heart attack!!!
But more importantly, Hendricks was aggressive while Romero liked to play possum. That gameplan would have helped GSP, since he would be happy to throw jabs for 5 rounds without opening up.
Let us also not forget that while Romero is dangerous, at that time he was still decisioning Brad Tavares.
And while you are correct about GSP's mistakes, all they have in common is that his losses were what caused him to be more careful, take no risks and follow his game plan. Which he did and that's why he didn't lose after Serra.
As for being hittable, it would be quite a feat if no one would touch him...especially since he went 5 rounds decisions time and again... so it is quite dishonest to even hint an expectation for him not to get hit at all.
The fact is: he did not open up and took any risks.
He kept to his gameplan and won expected decisions (which, if memory serves me right, is actually one of the main complaints about him).