Hybrid builds viable?

I want to do a fire+cold mage but am not sure how to itemize that. Mono damage is clearly simpler in that regard, so is hybrid even worth it?

Ah, “viable”… Along with “PTW”, “offensive”, and “ornithorynque”, one word that comes back all the time with very different meanings for everyone…

Fire and cold would both be spells, and both elemental, so it should work well enough to reach empowered monos and add a bit of corruption. But it probably wouldn’t go quite as high as a single damage-type build.
I suppose I would try to focus the cold part on crowd control effects like chill and freeze, and the fire for pure damage, with affixes adding fire damage % and freeze chance %, for example.

Sorry, not very specific, but again it shouldn’t be TOO hard to build and reach endgame.

Doing multipel damage types does work well, as long as the main damage skills you use share some kind of scaling options.

In your case elemental damage or damage over time (depending on the skills you want to use) would work.

Depending on what skill you will use for bosses and tougher mobs you might want to try and fit in some resistance shred for that skills damage type.
So for example if you clear monos mostly with a cold skill but doing single target damage with a fire skill you would want to try and get fire penetration and fire shred.

You definitely need to be a bit more thoughtful on your stat budget but you can definitely make it work.