>>13517740Regigigas suffers from several problems due to its ability:
-very vulnerable to status, generally forcing a moveslot to Substitute
-lacks good STAB/coverage to abuse its Attack (Crush Grip unreliable with halved speed + variable damage; Superpower lowers bulk+attack, its only two good points; everything else is low base power/unnecessary coverage).
Even after a Shift Gear, it's Attack would only reach 315, which places it comparably to a Pokemon with a +nature fully invested 105 base stat.
Not very threatening.
>But dat bulkDue to Slow Start, if you plan on going full offense with Shift Gear, you need to fully invest in Att/Speed, leaving no room for bulk, making it much easier to take down.
With Shift Gear, it's set would look like:
Adamant @Leftovers
252 Att 252 Speed (fine tune to reach break points later)
>Shift Gear>Substitute>Return>Drain Punch/Elemental PunchIt's coverage is still trash, you NEED Sub to reliably set up (though with it, you can get setup opportunities on slow bulky supporters) and it isn't threatening until after it gets at least two boosts. Your coverage will also leave you blocked by immunity (whether by typing or ability) or straight up Steel resisted.
It would not move to OU. It would not move to UU. It would not move to RU.
It'd just have another gimmicky set in NU, where it'll stay short of an actually useful move for it (Protect, for one, would allow it to Sub stall long enough to get going) or an ability shift.