This was brought up somewhere recently, so I did some research and found the answer in the March 1990 Club Galactica Super Report. This is a listing of the stat changes between the original 500 sets of Champions of the Galaxy 2087 and the 2nd (and subsequent) printings.
Characters unchanged: Star Warrior, Commander Sam, Massif, Renegade, Lord Nexus, Thantos, Executioner, Massacre, Mutant
L2O and L3O = Level 2 Offense and Level 3 Offense
Omega - Ring Rating from B to C
Wolf - L2O ch E to ch A
Beast Rider - Deathjump Rating from B to C
Actagon - L2O ch H to ch C
Proteus - L3O ch F to ch H
Pit Viper - Ring Rating from B to C
Pulsar - Ring Rating from B to C
Comrade Terror - L3O ch D to ch H
Brute - L3O ch F to ch G AND Deathjump Rating C to B
Vanity - PIN 6 (3) to 7 (4) AND Ring Rating B to C
Exo-King - L3O #2 out of the ring (c) becomes a deathjump (c) AND L2O ch G to ch C
Killer Queen - Turnbuckle A to B AND L2O ch G to ch D AND L3O ch F to ch H
Death Knight - Deathjump B to C AND L3O ch F to ch H
Krakan - L2O ch H to ch D
Ghengis Khan - Turnbuckle B to A
As mentioned before, the Choice Chart had references to the out of the ring chart instead of deathjump on ch G and ch H.
Finally, the out of the ring chart had an additional outcome that wasn't on later versions. Between "The opponent comes out of the ring to continue the fight..." and "In order to meet the referee's count..." there was an outcome that looked like this:
A - 6 B - 5 C - 4
You get back on the ring apron and shock the opponent with an incredible flying tackle over the top rope. The opponent goes down. OPPONENT ROLLS ON LEVEL 3 DEFENSE.
I think it's weird for someone who has "snapped" and gone wild, that they would be worse out of the ring. However, if you look at the guys who were downgraded, I wonder if it was Tom trying to put more distance between the tiers of upper, mid and lower card wrestlers.
The other idea is that even though Pit Viper was trying to be a wildman, he didn't have the necessary killer instinct to go all the way.
I think it's interesting to note with Actagon, Exo-King, and Killer Queen having a (ch G) or (ch H) on Level 2 Offense, they were probably tougher for the original 500 sets sold than the people who started playing later.
