Sounds good... you could chalk it up to the unique magical conditions of your world/planet that impede those kind of spells and effects... so you're not affecting how other planets/planes behave... just how magic just happens to function differently here on your planet. :sun

You could... [i]if borrowing from D&D[/i]... give such spells a greater chance of mishap if the caster isn't careful... such that they might arrive off target... and appear within a solid object (which shunts them to the nearest unoccupied space, dealing them damage measured by how far they are shunted), in the cushing depths of the ocean, high above the ground, in the middle of an enemy camp, or even in the void of space if the distance one attempts to teleport is great enough.