Yoshimitsu in older Tekkens looked pretty human. From what I know, Dr. Boskonovitch has modified him slightly before every tournament. What once was just a guy with a robotic arm is now almost a full cyborg. Another interpretation I have is that Yoshimitsu just rocks up to each tournament with a different suit of armour every time.

I love Tekken 5 (+ DR) and SC2. I like to think that I was kinda competitive at SC2 but only just. The local tournaments that used to be held around here boasted some real pros, most of whom would school me and day of the week, but I was some mild competition for some of the barrel scrapers =D.

I was a Cassandra man. Looking at the tier lists, I should be even better in SC3, but I haven't been able to find the time or the interest to make the switch. I got pretty swept up in the whole Tekken 5 arcade scene (Wow. There's a CARD xD).

In Tekken, I use quite a few characters (just like SC2) but my main is Lee. I tend to get smacked around a bit at arcades. I can't JF unless I have a controller (gonna buy a joypad to practice with though) and I'm not consistant with the really good juggles though I can land the simple ones every time (which is good for Lee since even the easiest juggle [launch, 1,2~f x 4, wall, 4,3,4] does criminal damage)

I have no idea why Heihachi isn't affected by the devil gene while his son, grandson, and father are.
Kazuya wasn't born with the Devil Gene, the devil entered his body at a young age after Heihachi threw him off a cliff. Jin received the gene through birth. This explains why Heihachi doesn't have the Devil Gene.

As for Jinpachi.. it's not stated anywhere that his supernatural power is due to the Devil Gene. I think we're supposed to just assume that after being locked away in underground Honmaru for decades, Jinpachi kind of went crazy.