Video games always have a lot of behind-the-scenes calculations that are hidden from the player, and the same applies to those that loosely fall within the RPG genre. It is a bit strange if you come from the tabletop scene where everything is very transparent, but tabletop RPGs also generally avoid computationally complex metrics. There's a balance to be struck between presenting useful information and overwhelming the player with it. I think the reason we haven't seen more things added to the character screen in ESO is because they want to keep the interface simplified. That they removed visibility of skill lines until a player does something with them indicates to me that they want to trim things down rather than make them more complex.