Uhg. I totally spaced on on seeing the flood of gathered materials this going to create. The way I see it they can allow catalyst to be gained like crystals (automatic), they can be materials themselves that are harvested/mined/fished off of current nodes, or they can add three new types of nodes - one for each class (or I suppose one that is usable by any class of gatherer).
And yet, this is also an opportunity to add entirely new game-play mechanics to DoL jobs which are even more limited than DoH in variety. Use current tools, nodes, etc., but have an option added to DoL that lets you get catalyst instead of your raw mats and introduce a new and separate mini-game different than the hot-cold currently used.
Alternately use existing mechanics with new options like allow the option (occasionally) to turn the gathered materials into catalyst as they are collected (similar to touch up?). Or make it a skill that equips and does it automatically similar to the random proc'ing of the other gather skills.
There's a few ways SE could capitalize on this opportunity that help (or hinder) the DoL to varying degrees on multiple levels. I hope they have taken this into account and planned accordingly.