VGC Mega-Venusaur Team: Help Improve

[Tridentbolt]

Below you'll see my VGC team. So basically, I wanted to make a team for fun, but serious at the same time. My favorite Pokemon's are Gengar, Machamp, and Mamoswine so I wanted to include all three of them in my team. Now for the rest, I needed some form of speed control so I added Togekiss with tailwind. Then I needed something to have a fairy destroyer as well as bulky psychics so I added Bisharp. Finally I added Venusaur because I used a team previously around Venusaur and I really liked it. So you can change any of the three other Pokemon as you like and with my favorite three, please give me any build suggestions or move sets. I really want to have a fun and decent team. Any suggestions is welcomed. Thank you.

Gengar @ Focus Sash
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
- Shadow Ball
- Sludge Bomb
- Icy Wind
- Will-O-Wisp

I wanted power with Gengar so I made it modest, but also wanted an element of surprise so I gave it a scarf to take out any Landorus-T jolly scarfs in one hit.

Machamp @ Sitrus Berry
Ability: No Guard
EVs: 188 HP / 212 Atk / 76 Def / 28 SpD / 4 Spe
Adamant Nature
IVs: 0 SpA
- Dynamic Punch
- Encore
- Stone Edge
- Protect

With Machamp, I EVed it to survive attacks from a jolly Mega-Kang with double edge, making it a 2 hit KO with Sitrus. I also EVed it enough to allow it to take 2 hits a Mega-Charizard Y using flamethrower.

Mamoswine @ Choice Scarf
Ability: Thick Fat
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
IVs: 0 SpA
- Earthquake
- Icicle Crash
- Ice Shard
- Rock Slide

I didn't know how else to EVed it so I left it like that.

Bisharp @ Life Orb
Ability: Defiant
EVs: 4 HP / 252 Atk / 252 Spe
Adamant Nature
IVs: 0 SpA
- Iron Head
- Knock Off
- Sucker Punch
- Protect

Just your standard Bisharp move set.

Venusaur @ Venusaurite
Ability: Chlorophyll
EVs: 220 HP / 76 Def / 60 SpA / 140 SpD / 12 Spe
Bold Nature
IVs: 0 Atk
- Sleep Powder
- Giga Drain
- Leech Seed
- Protect

I love the way I EVed this Venusaur. It survives a lot of attacks and it's reliable. It takes 2 hits of overheat from a Mega-Charizard Y under the sun and takes 2 hits of psychic from a Mega-Gardevoir. I couldn't be any more happier.

Togekiss @ Safety Goggles
Ability: Serene Grace
EVs: 252 HP / 180 Def / 76 SpD
Calm Nature
IVs: 0 Atk
- Air Slash
- Tailwind
- Follow Me
- Protect

This is my speed control Pokemon. It also helps to redirect attacks.

As you can see, I do not have any coverage for fire, water, fairy, electric, or psychic, so a Ferrothorn would definitely annihilate me.
With this team, psychic is my biggest weakness because three of my Pokemon are super effective to it. Five of my Pokemon take neutral damage from fire, a very bad thing. And four of my Pokemon takes neutral damages from water, dragon, and ghost, all of which are common in the meta game.

So as I stated above, any suggestions are worthy for considerations. Again, thank you for taking the time to review this.