I did worry about this, but I don't think it will cause a problem. All this odes is let a caster contribute when their damaging spells have run out, or to allow them to use their spells for more interesting things than hurting stuff.
What's more, it shouldn't outshine other damage dealers at any point. It's +1 to hit with 1d10+4 damage, while a pretty much unoptimised melee character might do 2d6+6. Plus, a ten foot range is putting them much closer to the action than any caster wants to be.