He is. Being a champion for an entire planet or in this case stellar empire, they should write him up as a more warrior approaching Beta Ray Bill or Superman in terms of combat prowess. Being a stellar empire that's the size of a galaxy, a warrior that losses the way Kl'rt had been written should have been killed and replace. Most writers just do misuse him to show up other heroes/villains - mostly from Earth.
1- Johnny Storm - Bubble him up and crushes him.
2- Colossus - BFR or hypnotize Peter to revert to human form and kills him.
3- Dumb Drax (without PG) - Bubble in the brain should put him to sleep.
4- Wonderman - See Drax.
5- Thing - See Wonderman.
6- Gamora - She's good but there's too many ways he can kill her.
7- Iron Man - Bubble him up and nova blast him till he turns crispy black.
8- Invisible Woman - Same powers except she's more experienced. He's more aggressive tho; I think he'll take her down because of this.
9- Hercules - See Gamora
10- Maxam - See Hercules
11- Nova - May or may not pass Nova.
12- Gladiator - Puts up a fight but he definitely stops here.
13- Thor
14- The incredible Hulk (Savage Hulk)
15- The Green Scar
I remember the time Invisible Woman beat the utter shit out of Super Skrull. Scenes like that are why he doesn't get any respect.
Every single one of his Fantastic Four powers are more powerful than those of the originals. He should be really powerful. Top Tier. His done pretty well against Thor in both their fights. A lot of characters that should be powerful that don't always get the respect they deserve do well in Thor's books. Firelord and the Super Skrull are an example.