I say there's always a place for customization in fighting games if done reasonably. SCV's was just far too in depth for its own good. Tekken 6's and VF5FS's felt just right. Axe out the silly stuff in place of items that FIT the character and there's a winning formula. They never distract me at all during fights. Instead, I take a large amount of interest in the many different kinds of combinations people come up with and the kind of awesome looking appearances I can make up with the equipment given. Customization doesn't keep me away from playing the game, but it keeps me coming back for more and more. I probably wouldn't have played Tekken 6 for as long as I have without it, and the same couldn't be said for Tag2's customization since that mode sucked donkey dookie in comparison.
I'm not trying to say TN should put customization into DoA5U / DoA6, because how else is TN supposed to milk cash via DLC with little effort (sarcasm)? I honestly see no place for a full on customization mode for DoA, but a Color Edit mode with a few accessories here and there to dabble in would be a major step for the series. And to be completely honest, I've lost faith in the new TN's ability to design an appealing costume that isn't boring to look at. Least they could do next time is give us a color edit mode a la CvS2 so clothing riddled down by variant shades of gray and white don't put me to sleep anymore <_<;
