No. Nonononono.
One of the things I like the most about D&D is the quirkiness of the spells and magic items. In a "roll your own" magic system, you almost never see spells like Evard's Black Tentacles, Changestaff, Bigby's Clenched Fist, "I prepared Explosive Runes today", Mordenkainen's Magnificient Mansion, or Rope Trick. Neither would you see a Ring of the Ram, a Ring of Shooting Stars, a Bag of Tricks, a Folding Boat, or various Feather Tokens. That kind of stuff is one of the main draws of D&D for me.
Evard's Black Tentacles is entangle + damage. Its one of the simpler to do.
Bigby's Clenched Fist is a damaging force effect. Casual.
Explosive Runes - Damaging + hidden + trigger. Simple.
Folding Boat is a simple conjurable boat that you can unconjure.
A feather token is a potion that someone put sprinkles on.
I want a player to create Bigby's Clenched Fist because they like punching people and its a convenient way to descibe magic in a role playing sense.
I want the numbers behing the scenes to be formula's that are easy to calculate and or modify without every spell being a special case.
A huge portion of the absues in D&D are based around there being too many special cases and not enough framework.
A swarm of insects that decend on the area and eat your enemies should be mechanically the same as a blast of lightning from the sky. Its annoying to have to look up each spell in each book and watch for wierd extra special stuff that may or may not have been thrown in instead of being able to know what the spell would do by formula.
Ever tried to make a uniquely flavored bad guy and then discovered they use the same spells as everyone else in the same ways because some spells are just better than others? That's lame. I shouldn't have to write up 15 spells so my guy can use almost exclusively acid spells. I should be able to change the energy type to acid for him and go.
I would rather give the formula's to the players to use there creativity and tactical abilty to figure out how to use the magic than to have them play librarian and look up the best spell or spells for a situation.