I know I'm late to this, and am also probably late for the holiday sales period to which this feedback process might have been attached and could have been targeting. Still gonna say my bit now that I have seen the thread.
At present it seems to me that it makes little sense to gather lower-grade materials for any other reason than to facilitate the system. When jumping into a new star system, there will always be a pack of G5 POIs for me, that then dry up. I assumed this was patched in as a concession to grind mitigation, either for everyone or just those with higher ranks. Best thing, no matter what you're looking for, is to just scoop up the fresh G5s, jump to a new system, repeat. I don't do it because I don't do things like that, at least until convinced, or I'd find myself wanting to quit the game right away. But I still gave up on trying to find a low-grade mat and just traded down. So yeah, in looking for lower grades, I've seen it seems to make no sense to gather them.
What purpose do random rolls serve? Would their loss really matter? You could make it so only low grades are random, but that runs you into the above problem. Right now, lower grades are basically one-and-done rolls. Randomness could be diminished on higher-grade rolls, especially successive augmentative higher-grade rolls, or removed entirely. Or perhaps instead of the current system, you could one-and-done every single tier, but have the exact numbers generated be random. So the exact numbers would bottom out at 50% or 66% of tier or something like that. This can then be augmented with successive rolls subject to diminishing returns or a count limit. Then that particular module's done. Sealed. This is more in line with usual crafting mechanics in lots of games. But I also really think that something like that only makes sense for higher grades, and maybe even makes no sense for anything below 5.
Missions for engineers for mat rewards or even just free rolls sounds good.
You mostly get raw mats from planet driving. Why can't manufactured mats be there in crashes or abandoned equipment and so on? NMS has these everywhere. Random sites like that do exist but as I recall they're pretty low-importance. 2 low grade mats and some cargo. Why can't you find a blowed-up cargo ship in a POI with a load of mat canisters full of low-grade mats?
Why can't settlements have some of this laying around? Go to a settlement, proc spawns ship hangar. Inside is a Dropship. Or maybe just ship parts, like a shield generator. Tools around. Ohh manufactured mats! Yoink! Geo lab. Raw mats. Yoink! Trash pile. Yoink!
We have trade beacons. Why not mat beacons? Like, if someone is in a system and they're farming mats, and they go back in to DSS, why not spawn a mat beacon POI that functions like a trade beacon does?
Whoa hold on there CMDR, I need to scan you. So you're scanning thing scans them in the hours-long walk they take to get to you and you notice they're looking to trade some mats. Hey, so while you're walking to me to scan me, could I take a look at those mats you want to trade? Oh sure! Be nice to get some mat trading in while I take this walk!
Basically you want to proc things based on what you think the player is doing right now, especially at higher rank/longer playtimes, and then this looks to the player like progression and functions like grind mitigation.
As for Mission board, this is basically BGS<->Mission board<->proc buildout problems. You want the proc to spawn more sights and sounds which enable a better BGS that leads to a deeper mission board.
I'm going to Colonia to haul on the CG. I'm taking a load of CG stuff with me. My original idea, seeing as I'm headed that way, was to take a passenger that wanted to go there, and this would hurt my jump distance less. Couldn't get one from the mission board when I looked due to various mixtures of reputation conditions and one not being there. Guess I could have jumped around and around until I found one but what would be the point? Maybe if there was a known jumping-off point for Colonia, because it had stuff that made sense for people headed to Colonia. Maybe if you funnelled people. Obviously Elite's a mile wide and that's good but maybe if you made these context-points or chokepoints where you could facilitate some of these systems coming together a bit better where context would appreciate, it might go a ways to making the proc more manageable and easy to build maybe. But then something like that becomes an "emergent gameplay" hotspot. Maybe something a little decentralized like a certain faction, certain region.
I like the missions for mats idea. At first blush, that seems like it could be really good. Make the trip out to an engineer, get a task which when done will certainly meaningfully advance your engineering process.