Except its not starting with 5 classes its starting with 3 that we know of so far...I'd argue it's the worst class of D3, pure edge fetish just for the sake of it, with high heels, goth clothes, and automatic machine guns crossbows. Out of any class ever added to Diablo, I'd stand firm that Demon Hunter is the worst fit for D4's atmosphere - and that it was only barely acceptable for D3's atmosphere, cartoony as it was.
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Mm, problem with Amazon being males isn't so much just Diablo's lore though, as it's not at all a Diablo unique thing. Having male Amazons would raise eyebrows regardless of how much sense it might make in Diablo lore.
IF we're getting Amazon, I'd MUCH rather they have two different female models rather than one male and one female.
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Let's not pretend that Diablo 3 had a rough launch because of a lack of classes though. I'd also argue that having a fuckton of classes isn't necessarily a good thing even - especially when each class is a separate model. If they manage to make the specializations good, what you'd end up with is an effective total of 15 classes (3 specializations each) just that they're shared across 5 models.
Starting with 5 classes is what both Diablo 2 and Diablo 3 did. I'd hardly call either game a failure, and I'd point none of their flaws to the initial roster.