that's what partner emblems do.

Spruigi's idea gave me a further idea. various different weapons, as he said, the heavier ones would give more power, but it also decreases speed and chance to dodge an attack. that is, if you include weapons in this game, if that is the case, please pardon my outdated knowlage.
And in my opinion, you definately want to throw in a battle that is kind of surprising.

Enemies using items in battle sounds appealing.
Using invocations os already supplied by emblems.
Weather conditions can be done, but would be limited by the types of weather in the rpg maker xp engine.

New Suggestion:

-Enemy Separate Part System, in which enemies are defeated by hitting different parts of the self. Some sort like in the bosses in the mario and luigi series.

A lot tougher to do with animated enemies, but knowing you, you've figured it out.

I got the ideas
Jump
Hammer
FireBrand:5 levels of firebrand
ThunderBrand:5 levels of thunderbrand
Specials:like Super Jump, Fire Orb, D-down Pound, Power Bounce, Multibounce, Hammer Smash, Finnese Smash, Flare Smash(firebrand+hammer)
Thunder Smash(thunderbrand+hammer), Poltergust 3000, Chidori:advanced physical electric attack) and Razengan:advanced physical fire attack)
3D flip:gives mario more agility, Head Bash:luigi launches himself to the enemy for a colision corse, counterstance:counter attacks from enemies.

Enemy Battle System
includes enemies counerattacks with certain attacks like the goombash, charge,and areal slash
enemies having weaknesses like the goomba weakness is any jumping ability, ice enemy weakness is fire and water enemy weakness is thunder.
Enemy part system:enemies having more than one part to take down.

Thanks for the input, but I think we already made those.

oh ok then