Personally, I am an Orion fan and I do think he is very powerful. But, he is not anywhere near current Thor. Thor, one shotting Ulik, doesn't do much for the Orion argument.
Classic Thor suffered from "Superman Complex", where he held back very often, obviously, saving his most powerful attacks for the most powerful enemies.
Ulik, at his best, has been able to beat Thor (as I posted above) and has also been a severe threat to Thor.
Orion fully geared is arguably more powerful than Thor. He is a peer of Superman.
Physically, anything close to Superman is beyond Thor. But let's not go there. You can't base Ulik's level off fighting Thor, no matter how many times he fought him. You have to look at other instances that tell whether Thor was written down to Ulik. All other instances point to Thor being written down to Ulik. Classic Thor has struggled many times against beings and things that a high end Thor would laugh at. Look at the Gladiator Colossus fight, what about the Thor mongoose fight, what about the Colossus Hulk fight where Colossus won, etc.
Ulik wasn't designed to be a class 100 being (or a very low one at best) as you see in his appearances outside Thor. He is very skilled, has tremendous heart and aggressiveness. This makes him more dangerous than his lower end strength says.
In forum rules, we argue current characters. That means Ulik is around Colossus level since nowadays Thor can one shot him.
Well best showings if they are current. Otherwise, things gets desperate and not reflective of how characters are currently portrayed.
Also showings AGAINST CHARACTERS go both ways. Either it was a good showing for Ulik against Thor in the past or it was a low showing for Thor. How can we decide which is the case? Outside showings is the key.
Was Colossus against Gladiator a good showing for Colossus or a bad showing for Gladiator? Was Spidey against Firelord a good showing for Spidey or a bad showing for Firelord?
Instances can range from extreme PIS to slight contradictory.