As a map maker I won't use those bigger rock piles though. They give you too little freedom as to how you want the rock placement too be. Makes them too easy to spot.
Stop putting small rocks everywhere
If you are below 2k then manually reclaiming the rocks doesn't really matter. Sure you will do some with your first 1-3 engies but what else are you gonna do, watch your factoruy build the next engie because issuing simple orders like mexes on maps you know takes only a couple of seconds? After that there is 0 need for it, you can do perfectly fine without it and most people would probably GAIN rating if they would spend that time micro'ing their t1 units.
I don't think I'll stop placing small rocks. I place big rocks and wrecks for early game reclaim targets, and small rocks for aesthetics and late game attack move engineers. They serve different purposes. Admittedly on maps of mine like Stickleback I could replace some of the rock bundles with geothermal style rock groups but then I have to worry about the aesthetics and the disproportionately large reclaim the geo rocks provide.
Edit: one of the maps that I think gets the balance pretty perfect is Twin Rivers.