Plane Sailing said:
I've just got to pick you up here - fireball and lightning bolt are hardly the powerful spells which they used to be. 5d6 damage in an area effect is perhaps OK for clearing out a lot of weak, CR1 or CR2 creatures (but then the fighter/barb/etc could do that with great cleave) but against foes of equivalent CR it is vastly underpowered compared to the old days... everything gets CON bonuses now, and that really ups the hps of characters and monsters.
Fireball may be an iconic sacred cow, but it isn't a tremendously effective spell, merely useful in some circumstances.
Furthermore, the clerical disparity in spells starts to become most significant from 10th level (5th level spells) onwards
They are weaker compared to an old 2nd edition fireball or lightning bolt, yet they're still the best available area effect spells at that level. Cleave occurs regularly, but monsters don't always line up nicely for Great Cleave. In addition, fighters have to be in harm's way to have a chance to attempt this, so I don't think they really compare. At later levels, I think both wizards and clerics have access to real showstopping power.