About Focus Punch/Superpower, yes Gengar uses them of 65 Attack. However, it's not correct to say "it's still strong" because it isn't; Blissey is just weak. Without investment which Gengar needs elsewhere (as will CAP8), even Blissey can still take the blow.
Code:
[B]Gengar:[/B]
0 Superpower vs. 0/252 Blissey: 36.87% - 43.63%
252 Superpower vs. 0/252 Blissey: 50.69% - 59.91%
0 Focus Punch vs. 0/252 Blissey: 46.08% - 54.38%
252 Focus Punch vs. 0/252 Blissey: 63.59% - 74.96%
0 Superpower vs. 168/120 Snorlax: 29.03% - 34.59%
252 Superpower vs. 168/120 Snorlax: 40.16% - 47.32%
0 Focus Punch vs. 168/120 Snorlax: 36.18% - 42.94%
252 Focus Punch vs. 168/120 Snorlax: 50.10% - 59.24%
Yeah, Gengar doesn't get Superpower, bite me. It's for reference. CAP8 will be doing slightly less damage with the corresponding moves.
Focus Punch takes extraneous setup, and this completely ignores that Blissey can't touch Gengar (especially behind a sub), meaning it's not even an ideal switch in (it'll stall with Recovery, which it can do Focus Punch or no Focus Punch). Blissey CAN touch CAP8 though, and its really sacrificing moveslots just for Blissey. It should be noted that Superpower is going to deal less damage during the second hit as well, whilest making CAP8 more vulnerable to physical attacks (go go Dugtrio). I fail to see the danger with these moves and I feel you may be overestimating their effectiveness. I can understand Selfdestruct and Explosion though. What the hell is Volt Tackle gonna hit that makes it so dangerous?