Yeah, Gengar really wants a fighting attack for the insane coverage it offers with Shadow Ball. Also, Bronzong is really concerning. If you are using Hypnosis/Dream Eater (which I would not recommend anyway) DO NOT use Psychic along with it. You getr completely walled by Dark Types as well as Bulky Psychics. I really suggest a completely new set. Anyway, Big Root gives 30% more recovery with HP stealing moves. For something like Bronzong, it seems rather pointless, when Leftovers will being doing more in the long run. It doesn't actaully boost the damage, you just get more HP back.
I use the following Bronzong (and pay attention to the layout of the Moveset, as people will take you more seriously if you post it properly...)
Bronzong @ Leftovers
Ability: Levitate
EVs: 252 HP, 40 Atk, 96 Def, 120 SDef
Sassy nature (+SDef, -Spd)
- Gyro Ball
- Hypnosis
- Stealth Rock / Reflect / Light Screen
- Explosion / Earthquake
This is an awesome lead, and Reflect/Lightscreen are useful in Double Battles. Use this with Gengar so you can take out two leads with Explosion and not suffer that same fate. Aqua Ring and Dig are both Bad moves, generally. Aqua Ring offers minimal recovery when you can Learn Wish. Wish gives both better healing and gives Bronzong some much needed Healing. Substitute could work over dig. Also, HP Electric is an option over Ice Beam, Although since this is a Wifi team, that could be difficult.