My idea is solely based on Dota character Invoker.
He uses Quas, Wex and Exort to combine them into diffrent spells but they also adds passiv stat.
In Invokers case Quas adds health regen, Wex attack speed and move speed, Exort bonus dmg.
And he can have 3 orbs floating around him at all times.
For a Invoker Warframe
Cold/Ice - Blue (Quas) orbs have health regen like wisp reservoir but player only.
Void Dmg - Purple (Wex) orbs have attackspeed and move speed also like wisp but player only.
Fire - Yellow (Exort) orbs have increased dmg/strenght - little bit like chroma.
(swapping the orbs around cant cost energy and combining skills can cost some energy)
Skill 1 would just circle the the orbs around and give bonus stat of any chosen orb.
Skill 2 would become a usable skill depeding on which 2 orbs that circle around you
Skill 3 would combine the orbs into a bigger spell on 4
Just a random though.
Might be overkill to have as many spells as the dota invoker because he has 10 spells.
just and idea really... i know its alot of work behind to make them reality.
it might be heavy copy right infringement to make a invoker in warframe xD