From a very noobiish perspective without diving into 5E, nor trying to mix max the heck out of it, I tend to not have that much caster in my party. I really fail to see the alternative to melee warrior, I think the main issue (at least from a very naive perspective) is the equipement. Basically you tend to find weapons with +1/+2/etc to rolls where at that point in the game I got two helmets that actually buff the DC for a spellcaster. So basically, my combats in short are : my warrior having two strikes at 80%+ chance to hit, and my caster having one strike at 50/60%. So yeah, I have versatility with the caster, but nothing that justify that much difference imo (and it's not even with accounting for the limited spellcasting due to the slots system, where I could bash for hours on end with a melee warrior)
