As much as I hate going to concerts - this would make me go to one!
I agree with you - I am generally not a fan of metal concerts. You wait in line forever just so you can get up front, and then you're surrounded by a bunch of sweaty metalheads who start pummeling each other the moment the first song starts. Constantly having to turn around to make sure some asshole won't elbow you in the back of the head is pretty annoying. To add to that, it generally lasts 4+ hours, so you have to stand there the whole time without drinking anything, because if you drink you'll have to urinate and when you leave and go to the bathroom you lose your spot up front.
I'm only about 5'6'' so I have to be up front or I can't see shit. The only other option is the balcony, but it's the same deal there - you drink, you go to pee, you lose your spot.
Another problem is that you have to stand there for 2+ hours watching generally sub-par opening acts just to have a spot from which to view the headlining band (which is the only one you care about). It's not like you can show up 15 minutes before the headliner plays and expect to get a good spot.
The only good spot I had for a concert that I wasn't fending off violent ghouls behind me was Opeth at the House of Blues a few years back. If you eat dinner in the restaurant prior to the show, you can get balcony access, where they have a bunch of tables right against the railing. That way, my friends and I could grab a table and sit and drink with a great view and no moshing behind us. Easily one of the best shows I've been to.
I think there should be a giant cage in the middle of a sunken floor (~1.5m deep) for people to mosh in. That way, the people who actually want to
watch the bands can stand all around the cage's perimeter and have a great view of the stage while not having to keep their guard up for wayward limbs. Moshers can enjoy releasing their primal urges in a controlled environment away from the general crowd who just want to chill and have a good time.
Moshing outside of the cage would be punishable by ejection from the premises and a fine.