Instead of having Shadow Sneak to become immune to Fighting moves, have teamates that can take them and beat the Pokemon using them. Why have Shadow Sneak when you can have some helpfl coverage move or U-Turn? Also, EVs in anything other that Attack, Special Attack, and Speed is just a waste.
If it is something you cannot KO, then that is a way better option than carrying Shadow Sneak, which 1) Isn't doing anything without Attack investment, and 2) Is a total waste of a moveslot, since Dark Pulse is not only stronger, but hits everything Shadow Sneak or Hidden Power Ghost hits as well. Keep in mind that Greninja can beat almost every spinner or Defog user.
Scizor and Skarmory are kinda hard for him I guess.
So then U-turning into a Ghost type after spikes is more Viable than using Shadow Sneak? If so, I can see this strategy being Viable. I might give it a try.