Magic builds are supposed to be bad? You can deny enemies the opportunity to act with ice, flash and witch's seal. Magic is more than capable of oneshotting enemies.
The good spells are
really good: Teleport, Soothing Waters and Elemental beyond what you listed, and Ice Shard deals good damage as using other spells in the same turn doesn't sacrifice crits.
However, the bad spells are absolutely abysmal: DoT and shielding spells (other than Teleport) aren't useful for long, if at all, because neither scale. Even when both sides are dealing into the hundreds of damage with one string of normal attacks, those spells continue to only deal the same 25/turn damage and 10/turn shielding that they did at the start of the game. It's immediately questionable to use them (even before considering that a weapon build sacrifices crits to do so), and they only fall further off a cliff after that. Teleport also doesn't scale, but it stays useful and eclipses other shielding purely because it starts at an obscenely high number.