can I use spell reflection to reflect Storm Bolt, for example?
You can use it for Pally Stun.
Ive used it to watch a shaman hex themself.
The 20% DR works on nature DoTs I believe and can be used against DKs apart from their ST spells.
Really only Rogue and Warrior are predominantly physical damage. Paladins, DKs, and enhancement have a lot of deflectable spells, nature, fire, holy or shadow damage that can be reduced by 20% even if not reflected.
Ideally you use it against hardcasts so you can choose things like Chaos Bolt, Greater Pyroblast, Hex, Cyclone, etc.
It’s harder to use effectively against an mDPS since you’re effectively guessing, but it is possible to reflect at least some of their spells. It’s usually worth using even if it feels like you’re just fishing.
Just watch out for the fake casts to trick you into popping it. You’re being kited and the Mage starts a Pyroblast cast is usually a sign.
Does spell reflect now work against condemn?
Even abilities it does not reflect, will still have their damage reduced as long as they’re not physical.