Fact without data? no. sorry that's your opinion. Just like what i've been saying is my opinion.
However I can back up with data/experience/history.
Number one complaint (for people who played the game and stuck with it, and didn't quit because it was 'too hard') of FFXI character creation: lack of customization
Number one praise for City of Heroes: complete and total customization. your appearance had nothing to do with stats. It was fun and exciting to see what people could come up with for a hero.
To really make a "great" game you need 2 things:
1) Technical and gameplay innovation.
2) High Quality Production Value.
for the first point, we're not getting a lot of that. it's SE so we know the campaign will be at least decent. (which is another big complaint for MMOs in general) but the UI and gameplay are likely going to be very similar to what else is already existing. largely because that's exactly what they said they were trying to do.
which leaves us with production value.
we're going to have houses and free companies that we can customize to a degree. we should be able to do the same thing with our gear.
it's not so much the need to customize our appearance as it is the need for the choice.
Hardcore gamers aren't going to care as much. but if they have the option they will exercise it. they also aren't likely going to be running around in swimsuits. in fact i'm near positive most people won't do this. although we might see an increase in people wearing coliseum gear, Vanya, and other visually appealing gear that we can't really use because the stats are garbage. It might happen for a little while. and you may have that one guy who's holding out because he really really like his Yukata and is emotionally attached to it. but eventually people will get bored with it and change their appearance.
Casual gamers however will flock to it like crazy. they will like playing dress up and running around with their friends killing monster their way. casual gamers hate feeling restricted and want freedom. being able to choose how you look is a good thing. there's nothing bad about having this option.
Gross exaggeration. that's like me saying everyone who argues against vanity slots boils down to saying this:
"I HATE CUSTOMIZATION AND WANT EVERYONE TO LOOK THE SAME BECAUSE I LIKE RODEO CLOWNS. I WANT EVERYONE TO LOOK UGLY BECAUSE THEY SHOULD FEEL BAD FOR WANTING TO BE PRETTY."
you can beat all content with AF. wearing better gear is not a requirement. it's about increasing your margin of error. why wear subpar gear and increase your chance of failure? it just doesn't make sense.
it's not about what is required. it's about options. no-one needs relic gear. no-one needs darklight. heck you don't even need double/triple melds. but we get them anyway and strive for it.
in fact with vanity slots you can add vanity gear as rewards. yay! more useless crap to collect! and looking at how successful facebook games are. I can say with confidence people like collecting useless crap.
You can see the proof of that with people who bought Chocobo barding.
why settle for 'good enough'?
that's like saying "Hey, I only need to own one pair of pants, one shirt, and one pair of shoes because it's good enough"
Everyone cares about what they look like. some care less than others, I will grant you. but we've all walked into a store. saw an article of clothing and said 'god no, I would never wear that.'
Yet it's perfectly fine to force us to wear clothing we don't' find visually appealing in a video game. >.>;;
we can just as quickly change gear with macros. in fact that's probably more efficient because you can actually share gear between gear sets without added complexity of needing aliases for gear. why not just increase the number of lines in a macro instead of adding gear sets?
oh wait. because it's easier. and adds production value. silly me.
If I had a choice between adding gear set slots or vanity slots I'd choose vanity. because macros are 'good enough' for gear swaps.
Furthermore if we're going the route of 'good enough' why do we even have more than 5 gear sets? we should all just upgrade our armor every 10 levels and then that's it. no more worries about what is best in slot. no more worries about this armor set clashing with that one. Everything is the same! so now there are no problems. I guess we can add in some additional armor past our level 50 AF set so people will keep playing.
we have multiple armor sets so we can customize ourselves and build our characters how we want to as we level. as armor during this stage is less important. but once we hit 50, we pretty much lock our appearance. this seems very backwards to me.