This has bothered me for over 10 years. When you are doing the main story quest and Abnur Tharn has you constrct a flesh atronach and says, "We'll make a Necromancer out of you yet." I'm playing on my main, a Sorcerer. Years later I hear they are putting Necromancy in the game. I'm really excited, then I learn it's a class, not a skill line. I've always said, "I wish any class can learn any skill, that's freedom in the game." It's over 10 years later and we will finally have the freedom to do so.
I've often thought, "You mean to tell me that a Sorcerer can not go invisible like a Nightblade, or a Nightblade can not learn how to cast a spell from a Sorcerer?" The list goes on and on.
Bottom line, Subclassing is awesome. This will get old and new players really excited to play Eso.
Thank you, Zos for adding this to the game.