I have to say that, while I’m playing GT5U and not GT6, I approve of a change where you prospect for ores by finding clues on the surface instead of digging vertical shafts.
Gregtech’s ore generation has always been a meaningful part of the appeal of the mod, since the dispersed, concentrated veins meant you had to explore, and potentially build a logistics network to bring ore from distant sites (I favor rails for this, myself).
The drawback is that ore prospecting in Gregtech has always been tedious, and sometimes very frustrating when you’re missing a key ore. Taking advantage of the 3x3 grid generation has always felt artificial and gamey, but playing with Ad Astera’s ore generation for Gregtech demonstrated how vital it was to have some sort of prospecting method. Absent the ore generation on a grid, searching a 3 dimensional volume was absolutely prohibitive. The vertical shafts on a 3x3 grid wasn’t great, but it was better than nothing.
The Seismic Prospector was a solution, but since it was gated behind 512V tech for the data sticks, there’s a long, long time when it’s unavailable. There are a couple of non-Gregtech mods for prospecting, but they either ignore Gregtech ores or report all of them as the same ore (something odd like hydrogen, IIRC).
Surface clues are much better.