Nope. You can completely reselect your entire spell list during every level up.

The first character I played was a sorcerer and I beat the game on my first try so the answer to your assumption is a resounding no.

The only difference between my first sorcerer and this sorcerer is that I intentionally went out of my way to avoid blasting spells this time. While I did go summoner with my first sorcerer, the summon only killed mooks. Once I was hit with a boss I killed his ass with a maximized missile storm. This time instead I did 0 blasting and only spammed summons.

So yeah. Just pick what spells look cool to you. Grab maximized, empowered, extend, and silent spell and go to town. Do whatever you want. If the spells you chose this level don't work out replace them at next level up.