Yamazaki is indeed one of the more versatile characters in the game, having a solid ground game, good air game, a command throw, a standing overhead attack, great pokes, high priority, lovely max mode potential and quite possibly the best character to corner someone with... possibly.
Poke combo off of B is something like:
"Crouch Ax2, stand A,

'Stapple' combo from close C is something like:
"Close C,


"Close C, Forward + A,

"Close C,

His sadomazo(counter) can counter pretty much any mid/upper attack in the game, however, it is the SLOWEST counterattack in 2002 and can be dodged with a well timed roll, that's not to say its not useful, far from it.
Yamazaki seems to have a tough time against Billy Kane, I myself don't think he has any other real trouble matches(Leona maybe?).
If I had to set up a tier specifically, I'd say that Yamazaki is at the same level as Ryo, edging close to the high tier, but not quite making it, due to the higher tier characters sometimes having an absurdly broken aspect to them(Leona close D combo potential for example) while Yamazaki remains in check for the most part.
I'd say he is at about 60-65%, if you take Billy Kane/Athena as 100% and Seth/Mature as 0%.
Discuss, the Orochi that(apparently) beat up Geese Howard in 1997.