As a Celestial scholar, I like Dragon's Breath as is. It's the highest power damage spell anyone takes, and it has a certain flair. One unique evocation spell is enough, though, like Prashka said.
Of the ones suggested after me, I like "I call forth a Dragon's Breath! 40 Flame!" best. I'm usually not casting fast enough for the extra words to matter. Another option is to require the IG incant to be done before throwing, but the damage can be called as the packet is going through the air, sort of how a fighter can call "two normal" as she's swinging, as long as it's done by the time it hits.
And Inaryn? It sucks very, very much. I like the idea of being able to change out elements for my spells. I assume the incants would be levels 1-4 blasts, 5-7 storm, 8 (Dragon's breath... and you'd probably have to come up with other names for the other elements, like Blizzard, Thunderstorm, Avalanche) for the highest level. If the damage incants were included, that kind of flexibility would possible... 'Course, I wouldn't say no to a damage buff. Aside from wands, celestial damage doesn't scale with level, and with monster body creep, it often takes a flame bolt to drop the endless respawn minions.
RiddickDale, binding isn't that useful in large quantities. Nearly everything I've run into resists, is immune, or rips free from binds. Those same things are often immune to commands, too.