A few more things to keep in mind:
- It's a 5' wide, 30' long, vertical stroke of lightning. In other words, it comes straight down into a 5' square. So, unless you're dealing with a situation in which one character is directly above another, or you've got more than one bad guy in a 5' square (which does surely happen, but not *that* often, at least not IME), it can only affect one character at a time.
- Unlike many damage-dealing spells, the damage done doesn't increase with the caster level.
- There's still a Reflex save for half.
So, what you get is a spell that'll do, on average, 10 points of electical damage (save for an average of 5 or so), with the one *big* advantage that you can use it 5 or more times over the course of a combat.
A good spell, yup. Not a broken spell, IMO.