Team building for pet battles is my favorite part of pet battling, and it could be so much better. In PvE you can get away with just building type advantage against most of the trainers. PvP battles there is more team building and synergy involved, like having all of your pets utilize a certain weather or lingering debuffs. But for the most part you still play pet by pet and the game play is pretty simple.
If there was another battle mode with 2 active pets on each side, it would open up so much more game play and team building complexity. You could make lineup that would have synergy and support within the active pets. You could have one pet set the weather and the next pet immediately use it with a move, or have one pet use defensive’s to stall for another pets 2 turn move.
There are tons of pet abilities that already interact with whole teams that would easily translate. Moves like Magma wave would hit both active pets and the back line pets. Luck Dance that buffs the teams crit would buff the other pets crit as well.
Then there are some moves that might need reworks for the double battle mode. Immolation that damages an enemy pet like a debuff, but it acts as a buff on the caster, it would probably damage both pets, but for balance for half damage. Stampede feels like it would hit enemy active pets, but that would make the already good move better, maybe it would also hit both for half damage and only apply its debuff to the target.
Another possible issue is the balancing. Some of the best pets in the game are ones that have synergy in their own kit. Ikky, that has black claw (adds flat damage taken) and flock (hits several times). The normal downside is that it takes a turn to setup, giving the other team time to counterplay by switching or using a defensive. In doubles the setup and attack is done in the same turn, meaning it can be way harder to counter the strat.
I imagine having 1 backline pet might not be enough for a good battle length, so maybe having a team of 5 pets for this mode would work. In the pet journal there would be a switch from singles to doubles mode for the 5 slots.
Anyway, i love pet battles the team building for all the quests and pvp battles. A double battle mode would add so much more depth to the mode.