fellow 90002-ers,
Just to let you guys know that I've fixed (or maybe altered) my 90002 problem
The problem is my network card.

It's been almost 2 weeks since the 90002 started from the August 4th maintenance and since that date it's been really annoying getting disconnected after every 3-5mins after login. Recently I've installed and tried my FFXIV on my 13" Retina MacBook Pro (via Bootcamp) and it runs fine and smooth under the same internet & wifi and that's what determined that it must have something to do with my PC hardware. My prime suspect is the network card and fortunately I have a spare and I swapped with my current card, started the game and been login in for few hours already without issues.

This may not be certain or accurate, I think the recent FFXIV update/maintenance somehow affects (or maybe hates ) my network card very much since that specific network card works just fine on other things except FFXIV.