To be fair the majority of people who used those effects in Oblivion were gaming the spell creation system to make insanely overpowered and unbalanced spells for a lot cheaper than a normal damage elemental spell. Plus there's always mods.
Considering spellmaking is gone thats really not a reason to remove these spells per se.
Yes mods will add back alot of things but not for console users. Also, whilst a case could be made that weakness spells are unfun / annoying to use, "Absorb health" is really a trademark of the RPG genre and Necromancy. It would be really terrible to see it gone, especially when you consider how easy it is to implement.