In the beginning of the Deathly Hallows, the main objective is getting Harry Potter safely from his current residence at Number 4 Privet Drive to the new headquarters of the Order of the Phoenix at the Burrow. This involved the hugely complicated plan of the Seven Potters with escorts and several homes being protected and portkeys and all that jazz. This plan seemed to me over-complicated for a few reasons.
Many of the threats could have been avoided if the plan was formulated and executed sooner.
I understand the Seven Potters wasn't the original plan, as Harry found out the day of the move:
"You, Harry," Dedalus continued, "will wait here for your guard. There has been a little change in the arrangements --"
"What d'you mean?" said Harry at once. "I thought Mad-Eye was going to come and take me by Side-Along-Apparition?"
Deathly Hallows, Chapter 3 "The Dursleys Departing"
But Dumbledore is a smart guy and was most likely expecting something like this to happen, where the Ministry of Magic would become untrustworthy and close to being taken by Voldemort, and Death Eaters ready to attack Harry around Number 4 Privet Drive.
Dumbledore's portrait even masterminded the whole scheme, with the decoy Harry's and Snape telling the Death Eaters the date of the plan.
Knowing these threats would be around when Harry would be moved from home, Dumbledore let the Order arrange to protect Harry from all these threats (which put plenty of people at risk) when really the threats could have been avoided in the first place if Harry was moved sooner. It seemed Dumbledore could have set up a different, simpler plan a lot sooner.
Harry couldn't call Number 4 Privet Drive home any longer.
For all of Harry's years at Hogwarts, he still had to return to Number 4 Privet Drive to call it home and be protected by Lily's enchantments, but he could only take advantage of this till he was 17:
"We can't wait for the Trace to break, because the moment you turn seventeen you'll lose all the protection your mother gave you." - Mad-Eye Moody
Deathly Hallows, Chapter 4 "The Seven Potters"
Forcing Harry to return to the Dursleys for just a month would eventually require moving him to another safe spot, which we saw unfold. If Harry had to be moved some point during that summer when he turned 17, he might as well have gone straight to the Burrow as a new protected home, instead of making him vulnerable in the middle of the summer. It did not seem like Harry had to return to Number 4 Privet Drive that summer.
Hogwarts was a very secure and public place, surrounded by many talented wizard and witches. It would have made sense to transport Harry immediately from Hogwarts to the Burrow.
So this leads to my question for a simpler plan:
Why wasn't the plan to move Harry to the Burrow right after he finished his sixth year at Hogwarts?
I'm looking for canon based answers, nothing from the harry potter wikia.