Ruin Explorer
Legend
You definitely wouldn't have to remove them to do what @BookTenTiger was suggesting. I don't think you'd even have to tone down Magic Missile. Maybe Fireball a little but if you just boosted martial ability to hit multiple targets maybe not even that, it'd just be relatively less powerful.What do you have in mind - Would you remove iconic spells such as Magic Missile and Fireball etc? Perhaps tone then down in terms of damage-dealing?
That said as long as D&D remains combat-centric, which I think any 6E would, every class should be good in and out of combat. The problem 5E has is that most casters shine in and out of combat, and this only gets more extreme as you reach higher levels, whereas non-casters don't do great out of combat except for maybe the skill-monkeys, but some of them are ALSO casters, like the Bard!
There's a pretty straightforward solution that a lot of modern D&D-like games are doing though, which is to make all spells require some kind of casting check, there are no automatic successes, which brings casters down to about everyone else out of combat.