I don't get why they would only ask the "DOA fans". They want to know how popular the characters are to the general populace so they can sell the most copies. That's pretty obvious. I bet DOAX sells to quite a few people outside the hardcore base that plays the fighters.
And tying a vote to money a) can't be easily cheated and b) actually gives every vote MORE weight, because it shows people care strongly about a certain character. If a ton of people kind of like Tina, but no one cares enough to spend a few bucks on a theme for her, how popular is she really?
It's not a completely unbiased poll of course, but if you think another poll would look significantly different, you're probably wrong.
I think if there was a bigger variance of body types between the DOA girls in general, the vote would probably look a bit different. But as it is you don't really have a lot of choices.
But they're not getting a view of the general populace. They're getting a view of a very specific subset of the populace, that doesn't even account for many of the players that would have played every DOA (and DOAX) game to date. Not only have I not voted on this, but without being on GAF, I'd have never even been aware of a vote happening anywhere.
I get what you're saying in regards to character popularity, and if someone isn't willing to spend money on them... but then that's basically what I was saying with my Shenmue III example earlier. There isn't really that many of us Shenmue III fans, but many of us were willing to dump far more than the average price of a game to see it made. That passion from the fans shouldn't be confused with popularity for the game though. It's entirely possible for something to be ridiculously popular, without generating much in the way of money (let's say 2048 for example), and it's possible for something to be rather niche, and still pull in stupid money (something like Idolmaster or Star Citizen would fit here).
And seeing as we're trying to consider all angles here, let's consider one more. I bought the DOA5 Ultimate Content Set and New Costume Pass 1. I still didn't vote in this. There's a difference in getting me to vote with my wallet for something I'm going to use, and vote with my walltet for the opportunity to vote with my wallet in the future.
It really doesn't prove anything about your point. I was pointing out the danger of idea you presenting 'less barrier gives more accurate result in statistics' which isn't true at all.
The poster above your post actually gave out good poll result which you probably already seen. Even in that one the result is almost same as 'voting with your wallet' result which we already seen.
Also, given that this game is not 1) a fighting game 2) most likely expansive fan service that lesser people are buying compare to DOA5 (which is evident by high price of game), gauging the interest of buyer with wallet is not a bad idea. This is not the same case as you are making DOA6 and making poll of who is going in and out.
Some people are playing specific character because of moveset and not because of character, and some people don't usually play that character at all but has interest in it, these are all margin of errors that can corrupt the result.
The voting for wallet in this case is actually a great idea to get accurate sample of gauging interest.
Having a low barrier to entry isn't the same as allowing unlimited entries. By allowing unlimited entries, you're effectively making the barrier of entry higher for everyone else. If 2NE1 fans are voting 1000 times each, then other people are essentially not voting if they vote once. The barrier is now voting as much as the 2NE1 fanbase.
I will accept your other considerations in regards to DOA5 though. It's true that someone's chosen character in that game may not be the same one they'd select in a DOAX game. That's a fair call. I'd still imagine that the overlap (outside of the smaller competitive circuit) would be order of magnitudes greater than buying themes (that most won't know exists) or conducted on a webpage in Japanese (that most won't know exists) though.
The approach they've taken IS a good idea for them. I'm not arguing that it isn't. But it's a good idea not because they want to know who's most popular (they don't really care).. but because they want to know which characters will generate the most revenue. It's not the same thing, even if it's possible it would result in the same list.