I played the game from the begining a few updates ago, and freezing is my most used spell (as the paralysis effect was the only way to defeat the busty elf for me), and i can guarantee that the paralysis works. Though i must admit that it may take a few hits to apply, and sometimes the enemy or Krowly died before.There are many times the game feels like Xcom. Take the spell Freezing for instance. There are some fights where it will just miss 4x in a row. To top that, Freezing just doesn't work at all. It says it has a 20% chance to paralyze, I've used it enough to get it to Freezing + and not once did it freeze or paralyze a single target. I have the blue flame crystal equipped and it wasn't until I got Freezing + that it finally froze a target. I remember playing like a year back and Freezing was a pretty powerful spell, it was how I beat the ghost outside the witch tower pretty early on. It's hard to justify ever using that spell, when icicle hits 3x and does way way more damage usually. Add to that it doesn't ever freeze or 'paralyze' a target and doesn't seem to have any synergy with the blue fire crystal (it's supposed to add 10% chance to freeze). Oh and another thing, Freezing is a slower casting spell, so even if you have high agility it will always cast slower than icicle too, it's a fun way to make Krowly into a punchingbag.
Remember that spells, as everything else in the game, progress based on proficiency (So to make them usefull it is nessesary to use them a lot and level them up.)