Paul Farquhar
Legend
1) Are you actually saying to players: "you can't play a spellcaster"? I'm not sure that would go down well. And if you don't, how do you avoid having a party of Angel Summoners in the land of BMX Bandits?With regard to 5e, why do think this. 5e, IMO, handles low magic games very well. You can play the game just wonderfully with all martial characters. In fact, I suggest the game might even work better if you do!
2) Even so called "martial" classes - rogues and fighters - have the majority of their subclasses with magical abilities.