Though I got started on BECMI D&D, I quickly made the transition to AD&D thanks to some books that my brother and I found at our local library. One of the things that I was interested in seeing in what we now call 1e was a second magic-user class called "The Illusionist". It was an interesting concept, a magic-user that specialized in a specific type of magic. The class even had it's own spell list, separate from those of the regular magic-user.
It wasn't long until I wondered if there were other types of spellcasters like the illusionist. I guess I wasn't the only one, because 2nd edition revamped the illusionist into the "specialist mage". Now you could play conjurers, necromancers, transmuters as well as the illusionist. But 2nd edition made one change that I wasn't happy with. Rather than the specialist having it's own spell list, there was a master spell list for all mages covering all spells. While it ensured that none of the specialists would be short-changed, it made the specialists less, if you'll pardon the expression, special. A straight magic-user can stock up his spellbook with all the illusion/phantasm spells and still have room for magic missile and fireball and not need a 16 Dexterity on top of it.
The only solution to this problem I can think of would be to pare down the main magic-user spell lists for the generalists, and to create separate lists for the eight specialists. But this seems to be a lot more trouble than it's worth. Especially when it comes to making sure no one class gets short-changed. It's strange that The Complete Wizard's Handbook didn't do a better job to make the specialists more unique. In hindsight, it seems that rather than try to create a broader magic-user with the potential for specialization, it would have been better to visit the new specialist classes individually in either a splatbook or a series of article in Dragon. Streamlining may have seemed like a good idea at the time. But in the end variety turned out to be the spice of life, an gaming.