Actually, it would deal considerably more damage than a fireball. As a straight wall, any target that isn't immobilised can move out of the wall, only taking the initial 5d8 damage. However, if you could bend the wall as I have illustrated, it would be impossible to step out of the wall without stepping back into it and taking an additional 5d8. So damage would be 10d8 (55) minimum, compared to 9d6 (32) for an equal level fireball.
Also, if a bent wall where allowed, rather than tight packing it could snake through a group of enemies whilst avoiding intermingled allies, reproducing the effect of Sculpt Spells/Careful Spell without needing to be an Evoker or use that metamagic.