Yeah I can see how weak the Carnage FTW argument is beginning to look.
Okay here's basically where I'm coming from.
Carnage is as fast and nearly as agile as Spiderman, this alone will make him one tough cookie to crack.
IF Carnage can slice Abomination open with his blades and spikes he should be able to take this fairly easily no question.
If not, then Carnage has to rely on the tendril trick. Now he has used his symbiote to rip Venom apart, travel through cyber space across the nation to kill people, and instill nightmarish illusions in people's heads so it's possible he could/would against Abom.
Durability wise he's stronger than Venom, he should handle Abom's punishment more easily than Venom did Juggy's and Venom did that with a smile.
And quite honestly neither one of them are very bright so I think it basically comes down to the fact that Carnage is simply more versatile and more vicious. I can see Emil taking wins but I doubt it would be for the majority.