Well Gigalith has QuakeEdge, SR and Toxic. It is enough I think. But sure, expanded movepool, like E.punches would help it. And Luvdisc ain't that bad... Well it is but w/e, it is still embarassing when Luvdisc beats Pokes in OU xP And, ond **** I used in OU with my Sun/TR team, was LO Darumaka. The lil daruma was so fun to use xD The only drawbacks was Hustle miss, SR and Priority.
Darumaka? Was it even fast enough to keep up?
Anyway, Gigalith suffers from poor typing, similar to Regirock. It's only niche is as a stealth rock lead with sturdy.
what does Luvdisc beat in OU without a massive amount of support?
Modest Choice Specs Luvdisc with a little rain dance support beats...
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 4HP/0SpDef
Alakazam (Neutral): 109% - 128% (276 - 325 HP). Guaranteed OHKO.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 4HP/0SpDef
Dugtrio (Neutral): 303% - 359% (644 - 762 HP). Guaranteed OHKO.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 252HP/0SpDef Sturdy
Donphan (Neutral): 99% - 99% (383 - 383 HP). Guaranteed 2HKO. OHKO with stealth rock.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 4HP/0SpDef Levitate
Gengar (Neutral): 116% - 137% (306 - 360 HP). Guaranteed OHKO.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 252HP/100SpDef Flash Fire
Heatran (Neutral): 107% - 127% (416 - 492 HP). Guaranteed OHKO.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 4HP/0SpDef
Infernape (Neutral): 217% - 255% (638 - 752 HP). Guaranteed OHKO.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 252HP/100SpDef
Landorus (Neutral): 135% - 159% (516 - 608 HP). Guaranteed OHKO.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 4HP/0SpDef
Lucario (Neutral): 114% - 135% (322 - 381 HP). Guaranteed OHKO.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 4HP/0SpDef Thick Fat
Mamoswine (Neutral): 201% - 237% (728 - 858 HP). Guaranteed OHKO.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 4HP/0SpDef
Mienshao (Neutral): 133% - 157% (364 - 429 HP). Guaranteed OHKO.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 4HP/0SpDef
Tornadus (Neutral): 96% - 114% (289 - 342 HP). Guaranteed 2HKO. 79% chance to OHKO. OHKO with stealth rock.
252SpAtk Choice Specs Luvdisc (+SAtk) Hydro Pump in Rain vs 240HP/0SpDef
Volcarona (Neutral): 124% - 147% (462 - 546 HP). Guaranteed OHKO.
I still don't suggest using it though.