Magna Charge ably fulfills the need for a mechanical Swap Force Skylander. It's got an interesting duality about it, as do most of the other Skylanders of its generation; while his top half is obviously the offensive side, his bottom half has some interesting applications that make good use of the character's motif.
Your first impression of Magna Charge will probably be something along the lines of "It's a robot with a laser gun." And that's totally fine, because robots with laser guns have always been, are currently, and will probably always be awesome by default. But this Skylander's got quite the bag of tricks. Some might surprise you. Others won't, but they'll still be fun anyway.
Magna Charge's top half deals primarily with the gun in his hands and the ridiculous head on his shoulders. Naturally, you can upgrade the Magnet Cannon to deal more damage and even multiply in projectiles. But the other primary top half ability of Magna Charge is the Polarized Pickup, which allows him to grab enemies and attract treasure from a distance. If you've got nothing to grab nearby, some random metal doodad will suddenly show up.
Most Swap Force Skylanders fight with their top halves and move with their bottom halves. That may be true of Magna Charge, but only to an extent. Sure, you can increase the speed of the wheel that propels him around, but more importantly, you can upgrade his Magneto Ball, a special energy leash that allows him to drag his enemies around and hurl them around like pebbles from a slingshot.