So I realized I hådn't set up my port forwarding correctly for Battlefield 3 yesterday (had it rigged for defunct 360, not PS3) and rejiggered the ports correctly. Improvements have been observed.
Thinking DOA5 might be similar since the PS3 port use isn't necessarily as uniform as on the 360/Xbox Live setups, I ran across this:
http://portforward.com/english/routers/port_forwarding/TP-Link/TD-8800/PS3_Dead_or_Alive_5.htm
While not my router, presumably these are the correct ports. Anybody tried this out? I've just forwarded the ports but I haven't gotten a game in yet so I have no idea if this makes things better.