Characters that could've been very strong if they lived

[Shadow Phantasm]

Minato,Kimmimaro,Deidara,and Kushina would've been top tier if they didn't kick the bucket.

 

[Dannie]

Haku and Kimimaro has much potential.

 

[FemmeFatale]

Sakura-Originally a genjutsu type and not once did she ever learn or use genjutsu. Kishi could have made her a genjutsu speicalist master instead of Tsunade 2.0

The Hyuga's in general-Their eye is descended from Kaguya/Hamura and got left in the dust for the Uchiha.

Itachi-Even though he was already strong, he cashed out way to soon and instead of bringing him back as an edo i would have had him die during the war after he and MS Sasuke battle it out. (I probably would have had him train Sakura for a stint in Genjutsu. You want to be the best learn from the best

Kabuto- Love this dude and just as his Sage Mode was introduced he was defeated before we could even see the extent of it's capablities.

That's about all I have at the moment.

Sakura training under TsunAde improve or perfected her chakrq control, improving get talent for genjutsu.
I think she would be to op ,and Kishi wouldn't be able to explain it. Because she isn't special.

 

[UchiGod Itachi]

Characters who got cheated out of power?

1.Sasori- Could have turn gaara into a human puppet along with Chiyo & Sakura , Had a Mind Control Jutsu on Kabuto to bring Orochimaru Experiments and Edos, Orochimaru removed the Mind Control on Kabuto Sasori could have potentially took Kabuto Edo's for himself.

2.Minato- I don't know why he sacrificed his life when he could have just seal have the kyuubi in Kushina & I don't understand why he didn't fuse Sage Mode with Bijuu as Naruto said it was easier to gather chakra that way.

3.Tobirama- Could have used Edo tensei to revive legendary shinobi's like Hashirama & Izuna but couldn't survive a ambush by 20 elite jonin bysides have the FTG ?