Adding more spell slots would completly unbalanced the game, especially at higher levels. Basically truth be told you need to learn to manage your spells if you guys can't balance them out at 12 or 16 you guys are really going to have problems at 29. You really don't need a wide variety of spells especially being a necromancer. All you really need are your lifetap line of spells and your dots and you can handle anything. Then you throw in some goodies like Feign death. I usually keep my shielding spells memorized just because I have more room. Once you hit 16 drop gate and put in feign death, truthfulluy I don't know why you would get invis memorized because once a creature has you in your targeting it doesn't matter if you go invis, they still can kill you.

Naeeldar 19 Necromancer