I am a child of the 80's and 90's.  As such, I have a wealth of classics that could use a new start.

1- Rainbow Brite:  No.... Not the evil reboot attempt.  Lets kick it up a notch with a bit more steampunk-esque tech.  In the early descriptions, each color kid had unique story ideas but never a firm basic origin.  RB was a visitor from another world, but from "where" is never asked or answered.  Each color kid was a war prisoner in a battle they lost.... but they never say before that.  And where the ham hocks were the color kids Stormy, Tickle Pink, and Moonglow during the great escape.  My inner child wants to know!!

2-  Silver Hawks:  Man does this need a 3D reboot!  The Sci-Fi had so much to explore.  The exsistentialism of willfully trading meat for tech to be deep space beat cops.  So many aliens were hinted at, but were never truly flushed out.  And to add to the fun, it had an undertone of mafia noir that could have only made it better.

3-  Mysterious Cities of Gold:  They only found 1 city.  There are 6 more out there.  I love a good period show. 

4-  Bucky O'Hare and the Toad Wars:  This had more development than the actual comic, but the comic had more spectacular events.  Hell, Bucky's comic had a Q-ish mouse that seemed to follow the team around for fun and curiosity.  I would have loved to see where that lead.  The one major thing I want changed is Willy.  Either age him up (To keep Jenny's flirting from being weird)  or give him an arc like he needs to find a way home rather than giving him a magic door.  Let him be more invested in the ani-verse war.

5-  Cyber Six:   Gimme!  GimmeGimmeGimme!