I voted for yards/meters.
I can be a bit of a scatterbrain when it comes to math, when I'm also thinking of other things going on (which is what happens when playing D&D), so having to convert feet to meters in my head really slow play down for me.
I grew up with the metric system, my brain is wired that way. While I know that a foot is 30.48 cm and an inch is 2.54 cm off the top of my head, it doesn't mean I can
think in these units. To me, a foot
is 30.48 cm - a thing I put in my calculator when I want to see how much it is in something I can understand.
If you say something is 50 feet long, it says nothing to me. The first thing that comes to mind for me is 50 meters, which is over 3 times the length.
Now, 30 feet being somewhat equivelant to 10 meters is easy enough (you know, when you can easily divide it by 3).
But when I need to, for example, convert 55 feet to meters, I need to stop and think about it, taking me out of the game, or else I'll mess it up. The way to convert these things isn't second nature to me, so each time I need to remind myself exactly what I need to do to get to the number I want (divide it to get to the number of 5 feet units, which are about 1.5 meters - then I need to multiply the number by 1.5 in my head - which for me works by dividing the number in half and adding that to the total).
I'm sure there are people out there (with metric wired brains) that have an easier time with these things than me, but I can't imagine that I'm the only one that has problems with this. I can also imagine that there are people that totally trip over on these things, instead of just being slowed down by it.
So, arguing about weapon reach, or fitting into a yard/meter wide square is all fine and dandy.. When you don't have to work with this mess every time something concerning feet comes up in the game.
For me, I'd take all these issues any day over having to deal with feet again while playing a game with my friends.
Also, I understand there's this thing where feet
feel more archaic and all that, fitting better into a fantasy world. No problem with that sentiment, but when it has to come up in practice, during play, where it is purely a hindrance for many people, how does that weigh out?
Also, I'm fine with them being called 'paces' and having that be effectively a yard, or a meter, or whichever other thing you want to use.
P.S. Insisting on using a system of measurement while
"As of 2006, 95 percent of the world's population live in metricated countries"(edit: I thought this might've been incorrect, but it's not far off after checking), while the alternative is
"the official system of measurement in almost every country in the world" is, well... I would say something, but I think it would cross the line of a civil discussion.
Is it common sense? As far as my way of thinking goes, it creates barriers where there doesn't have to be.
I can imagine there are people that would like to play the game, but after trying it out they are put off by it, simply because everything is measured in measurements they can't work with out of hand.
In the end, it comes down to whether WotC cares for the RPG market outside of the U.S. (and maybe the U.K).