To make Bisharp a good pursuit trapper, I recommend giving it assault vest over black glasses to live draco's from the lati's better. The ev spread changes to 192HP/220Atk/96Spe and Adamant Nature. This also makes it a solid Fairy Check
Garchomp can tank physical hits very well and you dont need another physical wall in Rotom wash. So I recommend you to change Rotom to a spdef Sylveon as Garchomp loves wish support and Charizard Y hates Status. This also gives you a great counter to keldeo. Also, Spdef Excadrill is not that good in this team as you are very keldeo weak. I recommend changing it to a bulky starmie to have a reliable spinner and a second answer for keldeo. It can also play reflect type shenanigans.
Here are the sets to import.
Sylveon @ Leftovers
Ability: Pixilate
EVs: 252 HP / 220 Def / 36 SpD
Bold Nature
- Hyper Voice
- Protect
- Wish
- Heal Bell
Starmie @ Leftovers
Ability: Natural Cure
EVs: 248 HP / 16 SpD / 244 Spe
Timid Nature
- Reflect Type
- Scald
- Rapid Spin
- Recover
With Wish support, charizard also doesn't need roost, and as bulky dragons give it trouble, You could change roost to dragon pulse.
So just to summarize,
Roost->Dragon Pulse
Black Glasses->Assault Vest
Rotom->Sylveon
Excadrill->Bulky Starmie
Tornadus and Chomp look solid except you might want to consider toxic over fire blast as an impish nature makes it weaker.
Good Luck with the team and make sure to lengthen the descriptions so your post isn't locked.