Team looks good, but a few nitpicks:
Substitute Magnezone prefers using a Timid nature with 36 HP/252 Atk/220 Spe to outspeed Swords Dance Scizor. It's already very strong, despite that.
To make the most out of Genesect's Download, give it U-turn. Dropping Thunderbolt for Bug Buzz is also an option.
Giving Heatran 248 HP as opposed to 252 HP reduces the amount of damage it takes from Stealth Rock slightly, and that can make a difference. It's more of a support Pokemon if it goes the defensive route, so Earth Power isn't really needed:
-Lava Plume
-Will-o-Wisp/Toxic
-Protect
-Roar/Stealth Rock
Nature: Calm
EVs: 248 HP/252 SDef/8 Spe
Item: Leftovers
Ability: Flash Fire
Latios is currently walled by Ferrothorn. Hard. HP Fire is the preferred option for dealing with it; it can go over Psyshock or Roost.
While Ice Fang lets Gyarados hit Gliscor, Landorus, Dragonite and Salamence, the former 2 are hit hard enough by Waterfall and the latter 2 are hit hard enough by Stone Edge. Speaking of Stone Edge, it's one of the preferred options over Ice Fang; the other is Bounce, for a secondary STAB.
None of Landorus' current moves benefit from Sheer Force, since they don't have secondary effects. Physically-based Landorus is preferred on Sand teams, due to Sand Force:
-Earth Power
-Focus Blast
-Hidden Power (Ice)
-Psychic/Rock Polish/Substitute
Nature: Timid/Modest
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb
Ability: Sheer Force
Or you can go for Therian Landorus, who hits harder with 145 Attack, even though it's slower:
-Stealth Rock/Gravity
-Earthquake
-Stone Edge
-U-turn
Nature: Adamant
EVs: 200 HP/56 Atk/244 Def
Item: Leftovers
or
-Earthquake
-Stone Edge
-U-turn
-Superpower/Hidden Power (Ice)
Nature: Jolly/Naive
EVs: 4 HP/252 Atk/252 Spe
Item: Choice Scarf
or
-Gravity
-Earthquake
-Stone Edge
-U-turn/Hidden Power (Ice)
Nature: Jolly/Naive
EVs: 4 HP/252 Atk/252 Spe
Item: Life Orb
or
-Rock Polish
-Earthquake
-Stone Edge
-Hidden Power (Ice)/Explosion
Nature: Naughty/Adamant
EVs: 252 Atk/4 SAtk/252 Spe
Item: Life Orb
or
-Substitute
-Earthquake
-Stone Edge
-Hidden Power (Ice)/Swords Dance
Nature: Naive/Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Leftovers
Thanks for the feedback for starters :D
A few things though:
-Heatran has Earth Power so it isn't walled by other Heatran. (Heatran is quite problematic for this team). The separate move options you listed are good except I don't see a point for roar if hazards aren't set up.
- Latios has psyshock because of the lack of physical attackers on this team. Blissey walls pretty much everything on my team. Ferrothorn and other pesky steel types can be dealt with with Magnezone, Genesect and Heatran. Roost can go but it lessens Latios' survivability.
- I like your Gyarados set.
- Landorus is physical simply due to the lack of physical attackers on this team. Sheer Force was chosen as an ability due to the lack of a better one for physical Landorus. In hindsight I guess Sand Force is better in the event you face a sand team.