I have very often used a house rule for Clerics that they can NOT memorize the same spell multiple times just to force them to use the entire spell list and pull them out of the "Party Medic" mode where they only ever have Cure Light Wounds spells in their 1st level spell slots. I always justify this in game by saying that the gods don't like granting you the same miracles over and over or something like that. For the record, my Cleric loving wife dislikes this rule for Clerics, unless I replace it with the 3e style trade for heals. To compound my OSR heresy, I usually let her add her level to the die roll when she casts a Cure Light Wounds spell, mainly because she has notoriously bad luck though*.
Actually, when it comes to Clerics and healing magic, various groups I have played with have had different fixes for it over the years. One group decided that Clerics didn't need to choose their spells in advance, they just had so many spells/level/day provided they prayed and were in good standing with their church/deity. That actually worked pretty well for that group. Another group decided, and I stand with them on this, that there should be some Cure (wound level) Wounds spells between Light and Serious, so we filled in the blanks with some Cure (______) Wounds spells at every spell level. I don't recall the particulars now, but it was a pretty wargamer filled group, so we probably hammered out all the math and fixed any problems it may have caused with higher level Cure Wounds spells. Another group went a different way and determined that a wound level should be based on the level of the character being healed, ergo a light wound on a 0-level NPC might be 1 HP, on a 20th level Fighter it might be 15 HP, all based on a percentage of your total HPs. I forget what formula was used for each Cure Wounds spell, but they worked pretty well for that group too, and made Cure Light Wounds NOT a waste of time for the party Cleric when everyone was around 15th level.
I never really thought about doing this to Magic-Users too, but over on the Mule Abides today it was mentioned in the "Joesky Tax" section as a relevant House Rule. I think it would be easier to justify in game than the Cleric rule honestly, the "magic" center in the brain can only store those sigils and formulae once; trying to "write" the same ones twice (or more) would just overwrite the existing copy that's already there. I think I like it, and having multiple spells for the Wu Jen in my OA campaign hasn't come up yet, so I think I can slide it in to see how it works out. Has anyone else done this? Does it force even more creativity out of the party Magic-Users? Should I do this to my son the first time he stretches his RPG muscles and plays a spell caster?
*Seriously, we had to implement what we call the "Mona Rule" when she creates characters, otherwise it takes her forever. The Mona Rule states- If you have created 2 or more "Hopeless Characters" in a row, the rest of the players can each pick up a die and roll stats for you. It was created because of her, and so far it has only ever been invoked on her behalf; but on numerous occasions. Usually she will insist that she get to keep trying, and we let her, until it starts to hold up the game, or she argues that a character whose highest stat is a 9 and has multiple stat penalties would be "fun to try to play". My dice luck is the opposite of hers. My black dice are legendary as the "Dice of Doom", and I have rolled so many characters straight that had no stats below 15 I had to STOP using 4d6 drop the lowest.