I noticed some issues for hot spring water I had already reported on the suggestion post for hot spring water in polar chasm.

• The hot spring water can't be placed in the nether.
• When water is placed, or ice broken or melted in the nether, it should turn into hot spring water.
• The hot spring water can't be used for filling water bottle and drink it for Tough As Nails.

I had some other suggestions about hot spring water. I think some pools should generate in undergarden. It would be pretty logic since plants needs water to grow, and it would make this biome more interesting. And since it's the only source of water that can generate in the nether, it would take a lot of importance relative to Tough As Nails with the thirst and temperature.