Multiple chars work, but only if you have 2x the time. There's no point in going through the hastle of setting up a 2nd char, repeating all old content and future content twice if you don't commit to capping it every week. If you want 2 coil jobs but don't have 2 raid groups or time to raid in 2 groups, cap tomes twice, spam wod 2x as much etc, then you won't ever see the benefit of a 2nd char. It will just be relegated to a gimpy version using basic gear you could have done on your 1st char.

It's really only if you both have the time and desire to really play multiple "main" classes. If you don't then you just waste time investing in a digital paperweight.