I tried to keep your team as close to the original as possible, borrowing a bit from this article that also starred Mega Sceptile, placing in the Top 8 of Dutch Reginals. I hope these changes will bring you some success. Changes / suggestions will be in bold.
Sceptile@ Sceptilite
Timid | Overgrow
252 SpA / 252 Spe / 4 Def
- Dragon Pulse
- Energy Ball
- Hidden Power [Fire]
- Protect
The star of the team remains mostly unchanged. I would like to point out that you will want to have Overgrow as his pre-Mega ability as a sort of emergency power buff. Focus Blast, or any move with less than 80% accuracy, is – for lack of a better word – bad (with a few exceptions, like Sleep Powder). The concequeces of missing an attack are much greater in Doubles than Singles. For that reason, I suggest HP Fire to let you dent Bisharp, Aegislash, Scizor, Ferrothorn and Mega Metagross, all of whom resist the Grass / Dragon / Fighting coverage (bar Bisharp).
Mamoswine@ Focus Sash
Jolly | Thick Fat
252 Atk | 252 Spe | 4 HP
- Protect
- Ice Shard
- Earthquake
- Rock Slide / Icicle Crash
Mamoswine needs a bit of work. The bulky set is okay, but a Focus Sash can garuntee a good matchup with Landorus since you can get off two Ice Shards. Plus, with Bisharp on the team, Intimidators will have to think twice when they lead, meaning that Mamo will have less of a problem with stat drops. A basic EV spread is best, while also giving Mamo the ability to get Rock Slide flinches on slower Pokémon. On that note, however, Mamo's purpose is to handle dangerous Dragons for Sceptile. While Ice Shard might be enough to stop non-bulky Salamence, bulky Specs Hydreigon and his friends can easily take Ice Shards all day. You may find Icicle Crash will help your matchup against them (as well as Landorus and Thundrus).
Rotom-H@ Choice Scarf
Timid | Levitate
252 SpA / 208 Spe / 48 HP
- Overheat
- Discharge
- Thunderbolt
- Hidden Power [Ice] / Shadow Ball / Trick
I like the Scarfed Rotom. I don't have much to say. My only qualm is Trick. It seems a bit out of place. If you Trick off your Scarf, then Rotom loses the ability to Discharge Sceptile first and outspeed important opponents like Mega Salamence. I would keep your Scarf as long as possible. In the place of Trick I primarily suggest HP Ice to check Mega Salamence and Choice Band Landorus. Shadow Ball can also work to chunk Cresselia and Aegislash.
Thundurus@ Sitrus Berry
Bold | Prankster
188 HP / 192 Def / 92 SpD / 36 Spe
- Thunderbolt
- Hidden Power [Ice]
- Thunder Wave
- Protect
Hawlucha is the first casualty of my RMT. While Taunt looks good on paper, it's actually not that good of a Trick Room stopper. Most setters run Metal Herb and/or Fake Out support, meaning that Taunt is useless. Your team also lacks good speed control and isn't overly bulky. For those reasons, I have replaced the luchador with Thundurus-Incarnate. I took the set from Nugget Bridge. It speed creeps things that speed creep Breloom by one point. It survives Adamant Kangaskhan Double-Edge and Aegislash's Shadow Ball is a 3HKO. Thunderbolt and HP Ice are staple attacks. Thunder Wave is, in the opinion of many, the best for mof speed control there is. You can also priority Thunder Wave your Sceptile and get him the boost.
Bisharp@ Life Orb
Adamant | Defiant
252 Atk / 252 Spe / 4 Def
- Sucker Punch
- Knock Off
- Iron Head
- Protect
Bisharp is fine, but I strongly suggest the standard 252 spread. Bisharp's bulk isn't actually that good in practice, since he often attracts double targets. Similarely to why bulky Salamence don't run Double-Edge and why more and more bulky Kangaskhans are choosing Return is that recoil of any sort (in this case Life Orb) completely negates any bulk calculations.
Swampert@ Expert Belt
Modest | Torrent
252 HP / 228 SpA / 4 Def / 20 SpD / 4 Spe
- Earth Power
- Ice Beam
- Scald
- Wide Guard
Cofagrigus is cool, I'll admit to that. But his home is more in Trick Room, which your team is not. In that case, I narrowed the field to find the last member. You needed a slow Pokémon to work in Trick Room. You needed Wide Guard to protect Mamoswine, Bisharp, Sceptile, Thundrus and Rotom (all of whom have a weakness to spread moves). You needed something to check Terrakion, a major threat to your team. I settled on Swampert. The EV spread survives Double-Edge from Salamence, Return from Kangaskhan, and Draco Meteor from Hydreigon. It can OHKO Terrakion, Salamence, and Landurus with Earth Power and Ice Beam. It has a decent chance to OHKO most Hydreigon, and chunks Thundurus and Amoonguss. Scald is to get some nice Burns on Kangaskhan, Landorus, Bisharp, and Terrakion.
So there's the new-and-improved team. I hope these changes are managable. I tried to make the team so that Mega Sceptile could still be the main focal point, but could function without him as well. I do hope that these improve your team, and that you have fun with it.
