You seem like the kind of player who doesn't like long, status-induced battles and prefers fast-pace hyper offence. Well, you can't get by with no bulk at all, but I think a few changes here and there could make a world of difference. I'll try and to 'the Scilicet' and look at the team's threats first, then get on to the actual rate. I'll probably miss a few because I like to find out my team's flaws via testing, but I'll do my best ;)
Threatlist
Looking at the good ol' Team Magma Teambuilder you have a stellar weakness to Ice, Dragon, and Fairy.
Most Ice attacks come from Water-types, and you only have one proper answer to those – Amoonguss – who can't really do much other than Spore them. Salamence will trigger Milotic's Competitive ability, letting it sweep almost your entire team, plus it gets rekt by Rotom's WoW.
Dragon-types, while not the most common anymore, can still do a number to you if you don't have Hydra. A wee bit more Ice coverage will fix this.
Your entire team gets positively destroyed by the proper Fairy-types. Your only check is Bisharp, who takes neutral from Hyper Voice and any smart player will make sure to bring their Bisharp checks. This will probably be the biggest change I'll make.
Okay! So there are changes that need making. You also said that you didn't like Amoonguss and ws having problems with Fire-types, so I'll try and patch that up as well. By the way, I am really really sorry for how many changes I made… but when I made the small ones, it opened up big holes and it was this huge dominoes effect. You have every reason to not like it. I'm sorry :(
Your team pre-rate:
Your team post-rate:
(sorry!)
Changes in bold.
Salamence@ Salamencite
Jolly | Intimidate
4 HP / 252 Atk / 252 Spe
- Return
- Dragon Dance
- Earthquake
- Protect
Salamence is good. I know the raw power of Adamant is tempting, but with Jolly you outspeed things like Gengar which outspeed you when Adamant. You said you were having problems with Fire-types. Earthquake fixes that, and when combined with Dragon Dance it hits like a truck. The last change isn't necessary, but I find that Return is better than DE on a Dragon-Dance set because it doesn't do insane recoil and the damage difference is barely noticeable at +1.
Aegislash@ Life Orb
Quiet | Stance Change
252 HP / 252 SpA / 4 SpD
- Shadow Ball
- Flash Cannon
- King's Shield
- Wide Guard
Hydreigon is good, but not on a Salamence team. They combine too many flaws. Instead, Aegislash helps protect Mence from Fairy-types, blocking Hyper Voice with Wide Guard and KOing them with Flash Cannon. Shadow Ball is Ghost STAB and King's Shield is for protection. I like the immediate power of Life Orb over Weakness Policy, but don't be afraid to try it.
Serperior@ Meadow Plate
Timid | Contrary
252 SpA / 4 SpD / 252 Spe
- Leaf Storm
- Light Screen / Reflect / Glare / HP Ice
- Light Screen / Reflect / Glare / HP Ice
- Protect
Replacing Amoonguss as your Grass-type, and boy is it offensive. This is the Pokémon I'm least sure about, because I think Amoonguss works quite well, but this was the best solid Grass-type I could find. Leaf Storm is very, very strong Grass STAB. Protect is mandatory, while the other two are up to you. Dual Screens helps the team's bulk, while Glare can Paralyze Landorus. Or you can just use Hidden Power [Ice] to KO it outright.
Heatran@ Safety Goggles
Modest | Flash Fire
44 HP / 4 Def / 204 SpA / 4 SpD / 252 Spe
- Heat Wave
- Earth Power
- Flash Cannon
- Protect
Heatran is the ultimate Fire check in my opinion. It can hit everything but Charizard with Earth Power. Heat Wave gets nice spread damage and STAB, while Flash Cannon deals with Fairies. Safety Goggles give you a good matchyp versus Amoonguss, also letting you beat the Amoonguss + Gardevoir combo. I took this spread from a report on Nugget Bridge. It survives Low Kick from Kangaskhan after an Intimidate.
Rotom-Wash@ Sitrus Berry
Calm | Levitate
252 HP / 44 Def / 60 SpA / 148 SpD / 4 Spe
- Hydro Pump
- Thunderbolt
- Will-o-Wisp / Thunder Wave
- Protect
Rotom helps you check Water-types not named Gastodon and Swampert with Thunderbolt. Hydro Pump deals with the likes of Heatran and Volcarona, as well as Terrakion, Excadrill, and Tyranitar. Will-o-Wisp cripples physical attackers, but your team lacks speed control, so Thunder Wave is worth testing and will take opponents by surprise. The EV spread survives Solar Beam from max SpA Charizard Y and OHKOs 4/0 Landorus with Hydro Pump.
Terrakion@ Lum Berry / Focus Sash
Jolly | Justified
252 Atk / 4 SpD / 252 Spe
- Close Combat
- Rock Slide
- Double Kick
- Protect
I don't like Terrakion. I prefer Conkeldurr or Virizion. Still, I didn't want to change more of your team and Terrakion still works on paper. You could try Focus Sash over Lum Berry to win Terrakion mirrors, but Lum lets you check Thundurus better. Jolly is always the superior nature for Terrakion. Try your best to get a Jolly one :)
There you go. Once again, I'm sorry I had to overhaul it so much, but I do hope that these changes will help. I wouldn't be surprised if I made a major oversight and left out a huge threat, so don't hesitate to point out any flaws (and spelling errors)!
