There might be issues with the Quality system that might arise that I can anticipate. I don't know since I can't playtest it yet so I'm not going to whine about it. But it would be interesting to have a discussion on deep gameplay impact and to drop the surface level discussion of names and RNG which don't matter.
I'm not sure that the construction of high quality items adds any worthwhile gameplay.
(looping recycling and sorting)
A bit too self-contained and easy to solve once and for all. If recycling worsened quality and didn't allow quality modules then we could be "forced" (to reasonably efficiently achieve legendary end products) to have quality consideration in the whole chain that produces legendary items. It would start with T2 plates to produce T3 chips for T4 rocket modules to make T5 spiders etc. I'm not saying just forcing only this way would produce good gameplay though. The part about adding sorting everywhere doesn't seem very compelling, and you would need quality modules everywhere. But what I do think is that it is more of a step in an interesting direction. I don't want unique recipes for every quality and for every item in the game either. But I think the mods that do add a lot of complicated recipes have a small part right. Scaling quality with the complexity of the whole production supply chain seems a bit more compelling.
Suggestion/Idea:
What I could see working is something like "quality ingredients", for each tier. It can be fluids and items and maybe other things like heat as well. They aren't "added" to the recipe prototypes for each item, but the assemblers will accept these additional ingredients anyways.
I'm adding names here for the quality tiers not because I am suggesting these names for the names sake, but because it makes sense with the suggestion:
- Regular
- Clean (made by supplying water or steam to the assembler)
- Heat-treated (supply heat via heat pipe to the assembler)
- Liquid cooled (supply cooling fluid, which has it's own production challenges to make, as additional ingredient to assembler)
- Nano-restructured (supply new nano bots item as additional ingredient to assembler, nano bots are also hard to produce)
Liquid cooled makes most sense on things like chips maybe. The point isn't the exact details here, my suggestion is to add to all recipes the same "quality improving" additive (which can have an interesting and difficult way to produce) to improve quality, and the highest tiers would need all steps in succession for their whole supply chain. The recipe prototypes don't need their own extra ingredient, it works with all items modded or not without modifying the recipes. And maybe you can have different "quality additives" for different types of items, like intermediates or final products if you want.
Drawback: you can't get items with low amount of processing steps, like basic belts, to highest quality tiers. Regular ore can make cleaned plates which can make heat treated gears which can be used for liquid cooled basic belts. Without higher tier ores you can't get higher tier plates. Also if something requires both plates and rocket control units then the cleaned plates limits the product to being heat-treated tier. But that problem can be ignored or maybe worked around some way with how mixed quality ingredients are treated.
And maybe you can improve 2 quality by tiers at once if you supply the ingredients at once as well.
This means an item that creates highest quality tier items is logistically much different and quite a challenge to design. But lower tier items (like cleaned) "only" require that you add water pipes everywhere. This might be a bit too much hassle, the idea could be tweaked, please focus on the general point and come with improvement suggestions of the details
after the general system is ironed out or at least discussed somewhat.
To note: I think this would make bulk production of highest tier items less resource demanding than the current one since the process should give high yield as a benefit for consuming extra ingredients and complicating the production. The resource demand for the extra ingredients for quality might be about equal to the amount needed to produce the actual items, making a complete factory for Nano-restructured/Legendary only consume like 2x the amount of resources as a "regular" quality one, compared to 56x for Legendary in the FFF. So the output of highest tier items will be much higher which means you will be able to use highest tier everywhere. But only if you can deal with that much more complex supply chains.
Quality production recycling might lead to odd distribution issues.
Maybe it won't. But it's seems like it would be kind of weird of doing the same recycling at the end of every production chain everywhere. And if you want quality tier X everywhere because it is worthwhile to support it, is it going to be interesting to make these higher qualities? They can be made everywhere since they don't require any additional input (unlike my suggestion) but they take space that you might not want to give up. But it seems a bit silly to ship product that you can "easily" produce at use location (planet), but that might get annoying if you are going to have to recycle loop. And is it worth the logistics of shipping legendary assemblers and modules by rocket? The current quality system seems like it could be too annoying to deal with everywhere for all products, but not hard enough that it is an achievement you want to dedicate ONE location for that then sends out units to the other planets. My suggestion above would make quality improvement more like regular Factorio gameplay, instead of (what seems to me at current moment) an annoying an not very interesting addition as far as actual production goes. The quality system as described by Wube might make gameplay more interesting by requiring a larger factory that consumes more resources, but the re-circulation loop itself doesn't seem to make the factory building more interesting.
A minor one
is that I don't personally really enjoy tiers of machines as it is already. I don't think we should only have one tier of assembly machines and belts etc (though I've considered self limiting to that for my own enjoyment). But I've stayed away from mods that add additional tiers of production machines and logistics that just scale numbers without interesting mechanisms. The interesting part of a megabase is mostly how to build greater factories when the machines can no longer be sped up further. Simple multipliers on everything don't make for interesting logistics puzzles, it just gives you higher numbers without actually requiring more from the factory designer. The logistics of massive trains and buses just disappear with infinite capacity belts and assemblers. But the quality system doesn't give infinite improvement so maybe it won't hurt. And numbers going up isn't necessarily bad. We will probably still see amazing scale of entities anyways. It's a bit weird to have multiple ways to upgrade machines. Not as clean. But that might be interesting, to have more paths to consider and balance, a puzzle in itself which way to upgrade is most efficient and how much effort to put into that before the gains level off instead of just placing more.
Quality poles, radars and turrets seem like just an improvement. I could enjoy quality radius improvements of lamps and roboports as well.