Those who haven't done Second Dream and War Within, do not read after this line. Spoilers ahead.
This concept of mine revolves around incorporating Focus schools with this warframe abilities. This idea is a bit controversial as the grind needed to master all schools are steep. But still, this might make DE consider the concept and do it in their own safe way.
Passive: United - Upon receiving fatal damage, Broken Warframe ejects Operator and uses its broken bodies as a supportive exoskeleton for the Operator. Gives bonus health, armor and energy to Operator. Operator can Void Mode to self revive, or wait for timer for the Broken Warframe to self "boot" itself. YOU actually die when the Operator also receive fatal damage.
Broken Warframe launches forward a part of its Somatic Fibres, entangling enemies and constantly channeling Electric and Heat. Like a whip, move mouse to ragdoll around enemies. Pressing primary fire key will buff damage with increased energy drain. Pressing ability key again stop the ability. Holding ability key will make Broken Warframe to cut the fibres and let the ability to change to a less effective duration-based ability. Press to focus damage, hold to focus CC.
Broken Warframe will mark an area and automatically launch Somatic Fibres and target enemies and allies in AoE to steal its health and armor, or its shield and heal allies respectively. Duration based ability that can be manually deactivated upon pressing ability again. Upon deactivation or ability end, Broken Warframe will immediately retract the fibres and mass knockdown will be dealt to surrounding enemies upon all fibres retraction.
Broken Warframe will sacrifice a part of its body to allies to enhance them. Debuffs Broken Warframe related to the body parts used while buffs Broken Warframe's other stats that still remain attached to its body. Arms will buff/debuff reload and melee speed, legs will buff/debuff sprint and parkour speed, torso will buff/debuff health and armor and neuroptics will buff/debuff energy and shield capacity.
Broken Warframe assembles its broken body into a quadruped form, forgoing its weaponry and enhancing its abilities. Increased movement speed with attacks from all paws (moddable separately like Exalted weapons). All abilities get faster animation and damage changed to follow Operator's primary Focus school.
Madurai - Heat and Puncture
Vazarin - Cold and Impact
Naramon - Toxin and Gas
Unairu - Corrosive for Armored (Grineer), Magnetic for Shielded (Corpus), Viral for Health (Infested)
Zenurik - Electric and Slash