Now a "Young Yondaime" mini filler series wouldnt do too much harm now would it?
*sigh*
Please tell me that was sarcasm, that doesn't work on so many levels its not funny.
There is no "young" Yondaime, considering he wouldn't have been Hokage until he was an adult and considering we don't know his actual name, it would be a little hard to do a filler series on him.
You really need to grasp the understanding of the term "filler", it cant (or isn't supposed to) contradict the canonical story in any way.
Which means they cant just give characters back story if they feel like it, because later on, when Kishimoto actually decides to do something with the character, the whole thing looks stupid and a bunch of people get confused.