Yosharian
Arcane
You could, but Icy Prison is a staple of the build, there is no fire version of it. Going for Draconic bloodline instead of Arcane will cost you 2 DC, but boost your damage dice a bit.
Once you get Rod of Flaming Vengeance, all your nuke damage will be fire anyway regardless of spell, but overall you will definitely be losing DC every time you deviate from the selections made in the build.
Which is perfectly fine if you're playing on a lower difficulty, or are willing to sacrifice DC for flavor. The choice is yours.
Perhaps you could go for some kind of 'fire + ice' dual element theme, if it suited you.
Once you get Rod of Flaming Vengeance, all your nuke damage will be fire anyway regardless of spell, but overall you will definitely be losing DC every time you deviate from the selections made in the build.
Which is perfectly fine if you're playing on a lower difficulty, or are willing to sacrifice DC for flavor. The choice is yours.
Perhaps you could go for some kind of 'fire + ice' dual element theme, if it suited you.