Since one of the lasts updates the casting doesnt produce as much steam as before but I think it would be nice this few steam being at a higher temperature, so that we can get a little more energy from it.

The reason i lowered the steam output is that you'll need less coal to fill a belt of eg. iron-plates than you would in vanilla.
(https://mods.factorio.com/mod/Molten_Metals/discussion/6248bfa0e355e54bbb7b5186)
Before that it was possible to build a self sustaining smelter-caster array which would, in some cases, also produce more power than it needed to run.

I could add some kind of heater to heat up the steam so you can use the turbines later on. Since steam-engines have a max temp of 165, raising the output temperature would render it useless until you researched reactors.

I had a self sustaining factory just with the steam production of plates then, after updating the mod, everything was xd. But I think it would be a little bit more accurate that the steam were hotter.