Personally I would keep it where it is. I've countered Landorus-T many times with sets of my own. It's definitely a huge threat, but it's not impossible to stop in its tracks, in my opinion.
Also, why aren't Dugtrio and Staraptor Chansey in the Viability Rankings? Both those sets are great. I've been using Dugtrio Chansey and it walls the heck out of almost everything.
But anyway, I've been using this Scizor set and it works wonders.
Klinklang (Scizor) @ Scizorite
Ability: Clear Body
EVs: 120 HP / 252 Atk / 136 Spe
Adamant Nature
- Rock Smash
- Shift Gear
- Wild Charge
- Gear Grind
Clear Body prevents any Intimidate shenanigans when non-mega Scizor switches in. The only reason I wanted to use Klinklang was because of Technician Gear Grind + Shift Gear, and it sure hits like a truck, as Technician Gear Grind is technically a 150BP STAB move. The EVs mean that Scizor gets 400 speed, a nice round number, after one Shift Gear. I maxed out the attack for as much damage as possible. The 120 HP EV's are for more bulk, and also give it 311 HP- an odd number.
Wild Charge and Rock Smash are the only good options I could get out of Klinklang, as its Physical movepool is pretty bad, and the only other viable physical move it gets is Return. Wild Charge takes most water types by surprise if I haven't Shift-Gear'd, while Rock Smash is technician boosted and has a small chance to lower defense, which is always good.
Obviously there are some threats, such as any fire type move, and walls, such Max Defense Solrock Steelix, but otherwise, it is a great attacker.
252+ Atk Technician Mega Scizor Gear Grind (2 hits) vs. 252 HP / 252+ Def Eviolite Chansey: 398-470 (56.5 - 66.7%) -- guaranteed 2HKO
252+ Atk Technician Mega Scizor Gear Grind (2 hits) vs. 4 HP / 0 Def Landorus-T: 326-386 (101.8 - 120.6%) -- guaranteed OHKO
+1 252+ Atk Mega Scizor Wild Charge vs. 252 HP / 252+ Def Suicune: 236-278 (58.4 - 68.8%) -- guaranteed 2HKO after Leftovers recovery