Yes we did... both my and another GM in the same city. We both adopted this rule because it was too easy for a sneaky type level 1 character to one shot an "unaware" level 10 mob. (this equates to a campain wrecker)
So... removing the "move into or out of a natural 66" corrected this...everything became more even - I disagree that it makes it useless, it's just more balanced this way.
I am all about balance. If a creature is too powerful at the same level of the characters I will scale it back... if the characters are too powerful for the same level of the mobs then they are out of balance.
I had a level 8 thief sneak in and "assassinate" one of the party members whilst they were in camp. The thief was nothing special ...she just had 18 ranks in ambush and a good stalk/hide. They failed their perceptions and she "one shotted" a party member and then got away...
There was an outcry that I purposefully set THAT character up to die...which was wrong... it was random who she attacked. This was because they had stolen from a very rich noble, he then - of course - hired a tracker/assassin to kill one of them...or all of them. Oh, and they were all 10th too... it was so bad that I didn't even have her come back and try to take out the others...I felt bad and felt like it was a mistake. At that point we all agreed that moving into or out of a 66 is a BAD idea for both mobs and players.
TRUST me, I don't make any house rules until I thoroughly discuss it with other GM's and my players.
So, after that we just all agree that moving into or out of a 66 is just a bad idea.
Drev