Yeah, Invis Stalker, I was going to say - that is a VERY evenly spaced poll.
I hope, and I'm just spitballing here, that this isn't a really divisive issue. Whatever number they come up with, I would think that players will simply shrug and go with it.
As I said, if I was king of the world and I could decide, I'd go with more granularity simply because, especially at lower levels, certain spells are pretty obviously more powerful than others. Sleep anyone? So, you can either rein in the spells - multiple nerfs to Sleep - or you can spread things out a bit more. Maybe in a Spell Level=Character Level system, Sleep might be a second level spell and maybe Knock is too while Web gets bumped to third or maybe fourth level.
It just makes a bit more space to work with.