I actually think Expert Belt is just as good as Specs on Goodra. Goodra's movepool is INSANE. You have viable moves like Sludge Wave (nailing Clefable, Gardevoir, and Azumarill), Thunderbolt (fat waters), Power Whip (Gastrodon, Quagsire), Focus Blast (Bisharp and Tyranitar, Heatran too but to a lesser degree), Earthquake (Heatran/Ttar/Sharp/etc.), Draco Meteor, Muddy Water (Heatran), Fire Blast (Ferrothorn and Scizor), Ice Beam (Lando-T and Garchomp), and so on. You can pick and choose the coverage you want depending on what your team is weak too, and Expert Belt can bluff a choiced set and let you nail the switch-in (say you hit a Clefable with Sludge Wave, you can then nail the incoming Skarm/Scizor/Ferro/Metagross with Fire Blast) with the appropriate coverage move.
The big downside is that you lose the power to OHKO things like Skarmory after Sturdy, and beat CM Clefable in a 1v1 (since you outspeed), and so on. These CAN be very important.
Sure, you give up the pure power of Specs, but I find that being able to use Goodra's very good natural (special) bulk with that insane movepool is worth it.
Goodra @ Expert Belt
Ability: Sap Sipper
EVs: 156 HP / 252 SpA / 100 Spe
Modest Nature
IVs: 0 Atk
- Sludge Wave/Ice Beam
- Draco Meteor
- Fire Blast/Thunderbolt
- Focus Blast/Muddy Water/Earthquake