According to me, the gamplay would be lot's better if it was like Twinsanity instead of a generic dungeon crawler with character with little to no usefull speciality.
Think about each character would have his own gameplay instead of just different attack.
- Gill Grunt could use his harpoon as hookshot and attach it to far away target to travel canyon and climb up wall
- Flying character can really fly, not just hovering on the floor, flying like this http://www.youtube.com/watch?v=SeZMooLPAHI
- Trigger Happy can use his gun to shoot trigger target, and have shooting phase a bit like this
Also not so unique ability(because 32 unique ability to complete the game would be cruel to your wallet) Like: digging, invisibility, bombing, super strenght, rolling etc.
And elemental ability will be a nice +. Like instead of just oppening a door:
- The life skylanders can grow plant
- Water skylanders can enter underwater area
- Magic Skylanders can cast spell
- And tech can repair thing