Turdpress is enough of an incompetently coded train wreck, without trying to to turn it into ANOTHER thing it was never meant to be.
On security grounds ALONE it is the last thing I'd be looking at to make the basis of a service. But then I realize how mind-numbingly dumbass it is leaving the SQL connection in global scope, storing the connection info in DEFINE, leaving endless client-facing entry vectors open, allowing includes to output and set things when called directly, etc, etc...
YMMV.
It's a cute toy for a blog for grandma, but trying to use it for much of anything else is just taking a trip down the Chattooga River with Ned Beatty.
It did win that 2008 pwnie for M4ss 0wnage for a reason after all.