GGX on Dreamcast was a wonderful game. Johnny is played in a very pressure-oriented game using the Mist Finer in conjunction with those specials to create constant pressure. Using the pressure, he can exact strategies that normally wouldn't work if they kept on rushdown and instead had to plan around his Mist slashes.
Tekken Tag and Tekken 4 are by NO means a button masher's game. It takes an incredible amount of strategy to be good at the game. If you just do random moves, you'll be destroyed in high or even medium-low level play play.
Only weakness in GGXX is that you MUST play a rushdown offense to be effective. Turtling only gets you messed over.
I can guarantee you that Justin Wong NEVER would have lost to Servbot if he tried with that team I gave you. That team loses to almost no one, if anybody besides themselves. The simplest fact of the matter, is that in the hands of experts, a character's true limitations and capabilities come to light, and Mags/Sent/Cable with Storm just rise above the rest.
It's nice that you can easily beat the team I gave you. You're either playing against a lame-as-heck computer, or against a low-level player. True high-level gameplay is absolutely different than what you see when you just play casually on your Dreamcast or whatever its on.
You want to see high-level fighting game play? There's some samples in the EVO 2003 DVD trailer on
www.shoryuken.com if you want to see real skill. It shows the power of Magneto, and shows what some real Tekken 4, Tekken Tag, SC2, GGXX, CvSNK2, and MvC2 talents on it. It also shows some VF4, but I don't know enough about it to comment.