I agree with you, a mature system is better for sure. I'm sorry you lost all 15-acros, I've definitely been down that path before. But, I still may test the waters, by adding some acros early. We'll seeI do agree with adding acros to a new system is not a good idea.
I have new dry rock BB system and introduced sps after completing 30 day cycle with a shrimp.
Then introduced 15 acro frags and all completely suffered stn.
Since then I've been dosing biodigest and vodka to increase the bacteria counts and will endeavor with some easy Montis next month.
With the dosing of both BioDigest and Vodka, make sure to keep an eye on your PO4 and NO3 from bottoming out.