Well, first of all, both Jean and Taka were added to VF back in 2008 in "Virtua Fighter 5 R" (the previous version, before VF5FS), so, correct me if I'm wrong, but was MMA, etc. as popular back then (especially in Japan)?
Also, Taka is a returning character from VF3. They took him out in VF4, and due to fan demand, added him back in VF5R, so, that's why he's in the game. As for Jean: VF had never had a character that did Karate before him. Now, Karate is a rather popular Japanese martial art, so you could imagine why they'd want it in VF.
As for Jean's look? Well, if you don't like how he looks, just change it. VF5FS has hundreds of items for him, so you can make him look as non-emo as you want. He's a devestating fighter though, don't let his looks fool you. Jean's fighting personality is anything but girly.