ROC and N-400 a year later. What's the current status, and what are the trends?

[eckoin 211]

Since ROC takes over a year, for a marriage based Green card one qualifies to apply for naturalization a year after applying for ROC before it was approved. 

 

I've seen conflicting advice on whether doing so delays your naturalization (the ROC application is in queue and needs to be adjucated first), or whether it speeds it up (the naturalization arrived in queue and ROC is done at the same time by definition). 

 

What's the general current status? Will the recent changes (bypassing some interviews based on evidence and previous interviews) likely speed up ROC in general? 

 

And does applying essentially concurrently, while I-751 is pending, do more harm, more good, or it just depends? Does it depend on the local field office as well, or is it a black box?