"Do you know this from first hand experience " i'd have to say , yes, first hand experience. my first tanks back a long long time ago in a place far far away (give or take 15 year ago, eek i am like wow just thinking about how long ago it was). had nothing but nitrate problems. take my water to have tested or test myself and my nitrate where always in the red, was like grrrr. even if i was doing water changes it didnt help. so i stop useing the bio media and the nitrate came down. it was a pain for me and did learn from it back then. for fish only it was ok not too much of a big deal.
i would have to say , yes, replacing the bio media with LR is a good thing, debris trapped in the live rock will be eat and passed by the bactiaria and those it would not be a "nitrate factory" but should be fully submerge for that result and not treated as a wet dry/air gas exchange.
"old style of bioballs that have the sponges", those came out after i started this hobby , it was another way to try to improve the bio media but as we all should know sponges are a major "nitrate factory" and any sponges in our tank any where should be clean weekly.
now with my new system ,which is getting ready to be upgraded to a 125, i started with a nice DIY sump, i have made both DIY wetdry and fuge/sump all the time, my system has never has nitrates problem. i have better results running my fuge and its has made my happy with the out come and less work.