I don't see any real problems in using normal d&d spellcasting classes for a low magic world, as long as you have a coherent idea of what magic can and cannot do in this world.
For exemple, in Lotr, no wizard ever seems to master "fly" or "teleport" type spells (not even "levitation", nor "feather fall", etc…). Gandalf has to walk or ride all the way, he cannot "passwall" through the Moria gates, he falls with the balrog, he only flies on the back of a (summonned?) giant eagle, etc… Everybody, even wizards, goes on foot. So the Dm can say: no spells relating to magical movement in a d&d-Lotr campaign. And : "summoning" spells only relate to specific, "named" creatures (just as the DMG optional rule), it simulates a "pact" with creatures that may or may not come to help if they happen to be in the neighborhood. Etc… If the players are given a clear list of what is allowed and disallowed for their spell selection, i don't think it's a problem.
Does that inbalance the game by weakening the spellcasting classes? i don't really think so: after all, even in a "normal" d&d campaign, using the standard rules, you can build a wizard without any "flashy" or destructive spells. It can be a personnal choice: but it can be just the way magicians are in a given camapaign. And remember, the villains will not have access to the spells that do not exist in this world.
Does this "spell restriction" imbalance the wizard classes relatively to other, non-spellcasting classes? I don't think either : because, if the wizard can't personnaly fly, the enemy fighter cannot have "flight" cast on him, etc… And in a low magic world, he probably does not carry many magic, ability enhancing, equipment or weapons. Of course, it changes, but it does not really reduces, the tactical options of a wizard in combat. It even gives back some great value to spells pertaining to misdirection (illusions), or mindcontrol (fear, domination, hold person)…
Another thing : in low magic campaings, magic is more often subtle, mysterious and terrifying than spectacular - but it does not have to be necessarily "low level". If the camapaign does not support "meteor swarm", the thought that, for example, "wail of the banshee" is available to some necromancers, is imo enough to make wizards frigthening for a party. Perhaps, with such "toned down" spell lists, wizards will be less efficient against numerous opponents; but after all it's the DM's job to provide situations in which the spells can be applied with a greater narrative effect.