zarator
^_^
Plus, I fail to see how, through already existing types/abilities/moves you can pull off such a concept. Assuming we do not create anything new, how far can we go?Well first off, Shield Dust only prevents secondary effects from moves whose primary effect is to damage. This does not block Status Moves, or secondary moves overall which was what moi's concept wanted.
I also wouldn't call it simple when there's a variety of ways to pull this off. Whether it be an ability, a move, or favorable typing, you are able to block at least a variety of secondary moves. It does not mean "fast pokemon with Taunt".
Resistance to entry hazards is something already seen (Bronzong, Flygon), and certainly not something which discourage me from using them. Just because the opponent has Flygon, it does not mean Stealth Rock is an unviable option.
Thwarting the threat of Leech Seed would pretty much require CAP9 to be Grass-typed (which is not the best type difensively - just think that every possible secondary type which could give Grass a SR resistance open to a x4 weakness), or to have abysmal HP - which is not the best thing to do with powerful Bullet Punches flying around (how much Def would need it to survive CB Scizor BP?). Besides, a lot of OU Leech Seeders (Celebi, Breloom, Pyroak for CAP, Shaymin) have the means to combat opposing Grass types.
Trick is the easiest threat to counter. Just make this Pokémon mainly a Choice user, or give him Sticky Hold/Klutz. This is definitely possible, and could actually lead to a slight - emphasis on the word "slight" - decrease in the use of Trick.
To sum it up, aside from Trick, the other forms of non-direct harm (Leech Seed, Entry Hazards) are not in any way discouraged by CAP9 being resistant to them - entry hazards in particular. This quality would at best help him on a hit-and-run role (scout, choiced attacker) which really isn't the concept's aim.
If we want to bring CAP9 to the level that these moves are actually discouraged, we should allow CAP9 not only to be resistant to them, but also to block them and so free also his teammates from this burden. This can be achieved only through either a fast Taunt or through Rapid Spin. And sorry, but I fail to find any amusement or interest into creating a fast Taunter/Spinner resistant to hazards - maybe Leech Seed - and immune to Trick. A good Pokémon maybe, but unexciting and certainly not original.
About the other secondary effects, the only ones which come to my mind are statuses and secondary-effect moves. The former (which, if you cared about, was the "status counter" concept we discarded, basically), has some inherent flaws IMO. In fact, there are only 2 direction we could go about this. Either we make him immune/resistant to most statuses (and Fidgit already solved this idea to a large extent thanks to Vital spirit, Special bias and Poison/Ground typing) or we give it Guts/Quick Feet/Marvel Scale/Poison Heal (and we have already a handful of abusers like these in OU - Breloom, Machamp, Heracross) . Either directions are pretty much uninteresting to me. The latter thing - secondary effect moves - well... I thought we aleady created Cyclohm for that. You know, Shield Dust with suberb typing/stats goes a long way for these...
EDIT: Oh, yes, there is also the possibility of give to this thing Magic Guard... Altough I still keep my opinion. The fact that CAP9 is resistant/immune to entry hazards, Leech Seed &co does in any way diminish their viability in the metagame. And besides, using Magic Guard opens you to Trick anyway (which, as I said before, is the only thing which, if countered, would actually decrease - a blocked Trick is much worse than a resisted SR, you know, free turns FTW...).