It wasn’t always that bad. Boring, yes, but not missing chunks like that. Some early/mid-GT6 world gen changes made that appear, iirc.
I complained how easy it was to spot those non-generating chunks if you just made a flat desert world and flew around (and some veins would break the 7-block-tall rule as well…)
But instead of just fixing it you disappeared for a week and came back with the rewritten 6.07 world gen 
2 Likes