I think names are ultimate important, but some people are going too much after this one.
Apparently, "Viper" is used in place of Buccaneer in some Korean and Japanese MMOs. It also makes me think of assassin, like Assassin's Creed, which even the armor kind of looks like. But they don't really want to go with assassin because it sounds bad (even NIN's ability with that name moves away from it becoming Dream Within A Dream). So Viper works to "get around the censors", so to speak, by kind of hinting at "swashbuckler assassin flirting with the gray areas of the law" without outright cementing it as a "lawbreaker" or "evil" class.
Not to mention the two swords could be like the two fangs of a poisonous snake (viper) which kind of make me think of something like the "Wolf Fang Fist" from Dragonball.
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Personally, I find it more creative than "corsair" or "buccaneer".
Not to be snippy, but I think people are...being snippy. And using the wrong words. "Viper" is FAR more creative than "generic pirate class" which corsair or buccaneer (as names, that is) would be. It'd be like having a wizard class and naming it...Wizard. That's not "creative". Naming it "Owl Mage" is far more creative.
So people harping on the name are using the wrong word. It's not that it lacks creativity, it's that you don't like it and you want something generic, but you don't want your argument to sound like you're the one advocating mediocrity.
Now, it's fine to make that argument - "Wizard" is a fine name that immediately gives people a clear idea of what the class is...but it's not "creative". So stop lying about what you want. Don't say "The Devs aren't creative enough!" say "I dislike this name and wish they had gone with a more generic concept". Yes, that makes you an advocate for mediocrity and makes you the underachiever, not the devs. But it's actually a solid argument.
This "The Devs are lazy! (because I'm not getting what I want...)" "argument" needs to die in a fire. People here use it all the time.
Instead, just say you don't like something. You not liking something doesn't mean the Devs are lazy, and it's not a crime to dislike something, and it's not a crime to want generic mediocrity. Just be honest about that being what you want.