Gouken is not a tricky character but amongst the easiest ones
Matchup numbers don’t matter for crap if you’re at a level where you open threads in the NSD
There are character specific forums which are probably dead but you can get lots of info there anyhow, most things don’t become outdated randomly.
Hey there, Us Goukens still respond to any messages left on the character sub-forum. So you can just ask some questions in there.
Although most information is usually available.
I have done a very in-depth Gouken Guide for new/novice/advanced players found here:
Also information on How to practice Safe Jumps & Option Selects which are great for Goukens.
As well as a multitude of Character specific matchups tips and gameplay commentaries.
There are others which contribute to Gouken knowledge in different ways, search phunkism for newly discovered tech (Advanced stuff) for example.
As for Good/Bad matchups:
Bad: Adon, Viper, Akuma, Cammy (Due to spammable, safe armour breakers and excellent normals & pressure)
Good: I wouldn’t like to say, We’re capable against most. Depends a lot on the player: Zangief / T.Hawk should be easy in theory since we have a great fireball game but its not usually so easy vs. skilled players as they’ll walk you into a corner.