xyzulu Good observation..
Recently i encountered same observation when we were doing some trials for seperate db server to share load and increase performance, i had also discussed with Adam regarding and we concluded we can not use separate db server yet, not without manual interventions at least.
first, there's no dynamic updates happening in wp-config.php even if there's a dedicated DNS entry present for mysql, which is waste bcz it has no use as of now, enhance should utilize that DNS entry to use it in db host parameter in wp-config.php after detection of seperate db host IP.
secondly, separate db work fantastic in private network but unfortunately as of now enhance doesn't support private networking communications so we have to rely on public connection which will use bandwidth and add extra ms of latency!
