eamon
Explorer
It's a huge disadvantage because the wizard has terrible AC and low hitpoints. At first level the difference might not be huge, but with that hit-dice difference it's going to be quite significant, quite soon.shocking grasps being a melee attack isn't much of a disadvantage. The mage doesn't want to be in melee, but you can move, use the spell and move away in the same turn, and without any mechanic that allows the frontline combatants to lock enemies in place or discourage them from moving or attacking elsewhere, it's almost impossible to stay away from any enemy that wants to attack you in melee. The only way is to remain out of their range.
Compare it with a fighter's attack: it's going to do less damage, less reliably, and be tactically much more risky. Which is fine, as it's not supposed to replace a fighter, but it's hardly very powerful.