I think,  it would be nice to be able to see the level of other players

Yes, we are likely going to add this beside their class... Its nessecary with the new pvp level gap system.

a skill with 100 points in it should be needed to earn more vital "inspecting" knowledge about other players, creatures and npcs.  You have to earn it to see this info.

that's a nice idea, maybe the skill could tell you even what a pg is wearing.