Budokai 3 easily outshines Soul Calibur II in depth.
Also, I remember fighting Omega Shenron on Z3 mode with a level 55 Gokou. I recorded the match on VHS, with me winning. I landed a 100X Big Bang Kamehameha, big O. Shenron still had more health than me. Luckily, my ki stat was 20, so I could TC at the same cost O. Shenron could.
But now you bring up fighting him in DA, you have the benefit of capsule set-ups.
Remember that Gokou ranks second in capsule set-ups. This is what I usually use against O. Shenron:
Meditation
Kaiouken
Super Saiyan
Saiyan Spirit
Dragon Fist
At SSJ, which you can activate at the start of the fight rather easily, you get up to 135% attack power while having 130% base defence. Also, remember that meditation suppresses ki usage by 1/3rd. This means you can TC standardly with meditation at the cost of two bars of ki.
When fighting O. Shenron, keep your distance. If he fires ki blasts, deflect. Eventually, we get locked into a TC fest. This is what I do:
BEcause O. Shenron never dodges and counterattacks me, I outreach him with my ->PKK starter. If I land, then I simply do PPKKK. Gokou is always moving in his PPKK which can throw off Omega’s TC cancels, and if he TCs when I execute the final K, he will be put into a bad juggling position. Eventually, I win the TC fest making Shenron fatigued taking a breather. I punish him usually with this combo cancel:
->PKK(cancel) KKKK(cancel) ->KKP(stun), <-PP, <-EEE->E.
Usually does at least 1,500 damage, seeing as how O. Shenron’s defence drops 10-12%. If he ever TCs me, I simply repeat the combo. Gokou also builds great ki, and at max ki, he has 143% attack power, which is nice.
Depends which VF. It is definately not close to VF4 Evo. Remember that Budokai 3 has some balancing issues, so at the higher levels of play (especially at the master level), characters like Piccolo can always win against a huge amount of the cast.