Thank you @CCP_Psych for the update, and @CCP_Swift for generally participating in these threads. Happy that this iterative process is happening! 
I have one core point to make, broken into lengthy paragraphs. Sorry. TL;DR: Please consider leaving a “design out” to address the T1/T2 whole-belt-optimization gap, preferably by simply giving “mining waste” and “mining space dust” its own distinct name. It doesn’t have to be my suggestion of “tailings” nor @Mike_Azariah 's “slag”. Any distinct name will do.
(Background: this continues to build off my previous, initial feedback.)
Problem: As it stands, CCP is positioning itself in a lose/lose situation where adjusting “waste” numbers yields either suboptimal outcomes for T2s or newbros in T1s. The fundamental emergent playstyle causing this issue is “whole belt optimization”, where groups in control of a resource “node” – whether a belt, anomaly, or moon chunk – wish to optimize for maximizing the amount gotten out of that particular resource node. In this scenario, “minimizing waste” is the player forcing function.
- T1 Waste > T2 Waste: This was CCP’s initial proposal, and I think we all understand and agree this punishes new players.
- T2 Waste > T1 Waste: This is CCP’s current proposal. What this means is players are not incentivized to skill to T2 versions for “whole belt optimization” resources like R64 moons. And players using T2 versions are punished, instead of newbros.
Perhaps this is a better outcome, but I posit a still-suboptimal one. Since “waste” is the only number available to CCP to adjust for this gameplay, you can see from above that no matter how “waste” is adjusted for T1/T2 relative to each other, CCP doesn’t have a lever to adjust “who gets to be better” for this particular problem, just “what kind of skill-level capsuleer” is getting frowned upon for this kind of gameplay.
This can be avoided by CCP considering additional design work to turn “waste” into a secondary thing more, somehow, in the future. That provides a positive feedback loop to “waste”, which means CCP would have a lever to both control 1st-order effects around waste-generation (the negative loop, currently the only one), and then 2nd-order effects about “mitigating the negative loop” which hopefully involves player activity.
For a humble hypothetical vision, consider the following: we give “mining waste” the name “tailings” today. In two quarters, you introduce “tailings” objects that spawn in space as the “waste lottery” is hit by T2 lasers & crystals. Perhaps Type C crystals prevent these from ever spawning. Great, now we have “tailings” objects left after a clear belt. Now, salvagers come along and salvage the tailings to get small amounts of alloys (those reprocessable units of trace minerals). Now you have active gameplay that allows complex balance: you could put low-sec-minerals into high-sec tailings, null-sec-minerals into low-sec tailings, trit-and-iso into null-sec tailings, etc. Plus, this would keep salvaging on the theme of “salvagers come in behind ratters and now miners for the leftover scraps”.
This all starts today with giving “mining waste” a good strong name today that distinguishes it from “compression waste”. You don’t have to consider any other details about my proposal. Just please consider giving yourself that “design out” so you’re not trapped in a design corner today.
Thanks for listening.