So I'm still having trouble completely understanding something in crucible. Stuff you earn in campaign doesn't have any advantage in PvP right? Its all aesthetic? All rifles do the same damage, and no health advantages?
As far as I'm aware, level, damage number and defense are the only things normalised. This also means that, no, not all auto rifles will deal the same damage because fire rate and impact are still taken into account. A slower, high impact gun will hit more per round than a faster, low impact one etc. Two of different levels, but the same stat spread should be identical, in theory, minus other abilities though.
Other abilities like increased reload, healing on kill, more ammo in magazine and so on are still in effect. I believe, but am not sure, that the recovery, agility and toughness stats are also still active. Just not actual level bonuses.
Would be amazing to have an official statement on exactly what does and does not count.