A good impact for sure, seeing as how Cradily's purpose is special walling. A damn good special wall it could make too, check out what has been called the scariest threats of DP against it:
CS Salamence Meteor Swarm:
525 attack (max+) vs. 516 defense (max+), 210 power, times 1.000000: 153 - 181
CS Starmie Ice Beam:
492 attack (max+, which you won't see) vs. 516 defense (max+), 95 power, times 2.000000: 132 - 156
Scheme'd Azelf Psychic:
766 attack (max+, which you won't see) vs. 516 defense (max+), 135 power, times 1.000000: 144 - 170
Scheme'd Porygon-Z Ice Beam:
810 attack (max+) vs. 516 defense (max+), 95 power, times 2.000000: 215 - 254
I'm not sure what the best EV spread is for Cradily, and whether you want to drop special defense a bit for HP for better hit-taking or just nearly max both. Regardless, it won't be taking on Porygon-Z but really...what can?
While it does get special options now, I wouldn't touch them. Otherwise you wouldn't be able to take on Raikou and other beasts that still use Calm Mind. I'd probably run a similar boring set to the Advance standard:
Cradily @Leftovers
Earthquake
Recover
Stealth Rock
Stone Edge / Rock Slide
Stone Edge obviously gives it more power but my experiences with Cradily in advance had it running out of PP even with -Rock Slide-, so I can foresee that being a serious issue. You can always run Energy Ball or Grass Knot over Earthquake or Stone Edge/Rock Slide if you want to have the potential to hit those things "hard". In any case, always run a physical move for things like Raikou if this is your sole special wall.
You won't be hitting anything hard anyway, it's not like Cradily is a strong attacker. That's what I really don't like about it...besides setting up Stealth Rock, it can't -do- anything.