What would you choose? Should be a circle of weaknesses (Like fire, grass, water)

Fire, Steel, Rock (top of my head)
or maybe... Fighting, ice, flying

Hmmm... Fighting, Psychic, Dark. Mainly because those Pokemon look a lot cooler than the starters do. But I would also like a triangle that incorporates Fire, because we need more Fire type Pokemon.

With fighting, you'd be at an immediate advantage over almost all pokemon, so I'd not go there...

Flying would include normal or another type, so it is a bad idea.

Psychic would be ok, with bug and poison.

But I'd have to go with, perhaps, Ground, Ice, and Fire.
Fire isn't changed, but, it works well here, as there are few fire types anyway.
Then for their secondary types~Ground\Dragon, Ice/Grass, Fire/Steel
So we could have trapinch, snover, and a pre-evo for heatran that is only fire type...

That way, the attacks would all become stronger against each other, because I think the series needs a more challenging story anyway.

They would have to be all Water and had to be all lv.100 magikarps that learned Sky Uppercut, Blaze Kick, Fly, and Judgement because nothing could beat Judgement.

I'd like to see something like Water/Ice, Fire/Dragon and Grass/Water.

The double water would be different, but it makes sense.