Mekanism is different from most of the others. It allows you to scale your ore processing from anywhere up to 5x. The numbers are not the interesting part, though. The interesting part is the sheer amount of processing involved. A whole chain of chemical extraction and purification is required to set this all up. Ores must be infused with Hydrogen Chloride and purified with Oxygen, which can be collected from the atmosphere or separated from Water, etc, etc, etc- it's complicated! Secondly, you can scale it as you progress. Mekanism allows you to scale your ore -> ingot production at first 2x, but as your tech increases and you can perform those chemical processes, you can scale your ingot production up to 5x.
There's more info on the website, but this flowchart gets the idea across;
![Image](https://forums.factorio.com/images/ext/877f86f5441a912963757fa3d8f788c7.png)
I think a similar system would work in Factorio's favour. I'm not suggesting to rip off Mekanism entirely, but I think an additional production line of ore would play into Factorio's hands quite nicely. I don't know about you, but my metals production/demand tends to fluctuate as I progress through the game. Generally speaking, I have metals coming out the wazoo towards the start, but as I progress my factories begin to choke from lack of metals. The only way to counter this is to add more factories and expand outwards in search of more ore to freight in. It would be great if Factorio could capitalise on it's greatest strength as a game and allow you to build a grand ore refinery into your base! And if you still prefer doing trains, you can still do that.
As a side note, whacking ore into a furnace to get an ingot isn't the most realistic thing in the world. A quick look at the Wikipedia Page on Metal Processing will show you that. It's not the best point, I know, but if you're going to replicate Oil Refining to a degree, then why not Metal Processing?
But back to a more gameplay-centred argument; think about Factorio's future. It's still in early development. There's going to be more and more content to be added. Which means for the player, there's going to be more stuff to be built. More production lines to be added. More demand for metals. This will mean that the players will be forced outwards into the map find more metals sooner. Not only might they not be prepared for biters that early, but it will also mean that the player's control of the map will be forced to expand, and they will have to deal with the problems that brings, and more and more (more than it is now, anyway) of the focus, therefore, becomes having to deal with biters attacking your outposts, and that is a very repetitive process. So why not replace that repetitive process with one that isn't so repetitive. One that takes arguably more thought and care to perform?
Ore processing. S'the future. It's one of those things that's bound to be added to Factorio anyway. What do you guys think?