Well, considering that I'm the only one primarily falling under both opinions, I'll assume that that remark was made at me:
Johnny, I've been reading comic books for the better part of sixteen years now. That's a full two thirds of my life. In that time, I've found very few characters who were more a shallow, two-dimensional cliche of the time in which they were created. As much as characters like Wolverine and Punisher became cliches in the fact that many characters emulated them and thus the genre centered around rip-offs and homages to them, Carnage was a character who was created to reflect the popular effect of the time. There is literally no substance to him. He is merely a batshit guy with super powers. There have been precious few additions to the character that make him anything more than that. He is a character that has been around for over fifteen years and that's still all he is, a pale impersonation of the Joker and Venom. He fails to grow as a character because the template he was created upon had little to no room for development. There's a reason that, for all his notoriety, he's only ever had one real major storyline involvement, albeit a pretty remarkably terrible one that was actually outdone by a video game tie-in. Since Maximum Carnage, Carnage has barely been a presence of consequence.
Venom, well, he at least had some vague potential. The original idea was to create a kind of flip side to Spider-Man. This was a relatively new idea at the time. Unfortunately, Marvel botched it all to Hell. From his inception, he was a raving moron who hated Spider-Man because he caught a serial killer that ended up proving a story he covered to be false. He was incredibly powerful and he came out of nowhere to suddenly start beating on Spider-Man and going after him mercilessly for no good reason in some utter garbage deus ex bullshit. The initial idea behind the concept was for the Venom symbiote to be the real antagonist, jumping from host to host trying to kill or re-merge with Spider-Man after their separation and that could've been entertaining and sustainable. Unfortunately, Marvel blew the whole thing. He was too popular, so they decided to stick with Brock and turn him into essentially the Punisher with spider powers, again, a cliched product of the times. Over recent years, some depth has been added to Brock, but this didn't occur until right before Brock and Venom were separated, and Venom's new host is essentially a rerun of Carnage (He is currently bonded to Mac Gargan, formerly known as Scorpion). In effect, Brock has regained some semblance of interest, but Venom is still a pile of shit.
Bane was similar to Venom in his inception, but DC actually stuck to their guns on it in a rather ballsy manner. Bane reveled in his simplicity, while having some inner depth. Bane was a true threat to Batman that DC had been building for a while. He was a behind the scenes presence that had been working his way into the Gotham scene for a while before Knightfall occurred. He was blended into Batman's rogues gallery and set up naturally as an extreme threat, compared to Venom being shoehorned into the Spider-Man franchise. He was a much denser and much more enjoyable character.
I like my villains with depth or at least a great character. Magneto is an all time great. He's not some cheap thug, he wants to subjugate humanity because he feels they'll round his people up and slaughter them like humans did to his own family (He was a Jewish boy in Auschwitz).
I'll admit, something could come along and change my mind about some shitty characters. I'm of the mind that there's no such thing as an inherently terrible character, as a great writer could always come along and make something out of them (Such as Magneto, who began life as a total joke), but as yet, Venom has had very little forward movement and Carnage is, to this day, a joke who happened to look cool.