In reality, his legacy is cemented and will be written long after we're all gone.
True...
Financed, armed, supplied, trained, protected, defended, enabled, and even dragged the US into 2 unauthorized wars to help terrorists, to include the group that slaughtered 3,000 Americans - later left Americans to needlessly die at there hands.
Supplied, armed, financed this nations' enemies (Iran, Russia, North Korea...)...armed Mexican Drug Cartels with the specific intent to facilitate murder in great enough numbers to give him and Democrats an opportunity to go after Americans' Constitutional Right to bare arms...failed to protect Americans from numerous terrorist attacks despite having been given prior warning and even the identity of the terrorists - facilitated terrorist attacks by brining a terrorist into the US and mocking Americans' concern over our security just days before the terrorist he helped get a visa murdered 7 Americans in Ca in a terrorist attack...paid ransoms for Americans held hostage...
Protected ISIS Black Market Oil facilities / assets, which funded 50% of its terrorist activities - after the Paris attack Obama refused to take part in the retaliatory strikes but instead dropped leaflets down to ISIS warning them the attack was coming...
Released the top 5 enemy commanders in the midst of a war in an attempt to keep a campaign promise to close GITMO - after their release one of the leader's tribe/group slaughtered an entire village - men, women, and children - in retaliation for their part in helping their leader get captured.
Violated both Constitution and Rule of Law - he and his administration were found Guilty of Contempt of Court Twice for disobeying Judges' rulings; his US AG became the 1st Presidential Cabinet Member in US history to be Censured (for his crimes of Perjury in an attempt to keep the Fast and Furious scandal buried), Administration members caught perjuring themselves (and were protected from Indictment / Prison or had deals cut for them to prevent indictment / prison) included US AG Holder, NSA Director Clapper, CIA Director Brennan, IRS Director Koskinen, Sect of State Hillary Clinton...Set a new record for Presidential criminal non-compliance with the FOIA.
Illegally spied on Americans, reporters, the media, US Senators, USSC Justices...and opposition party Presidential Candidates during an election / a US President...used the IRS illegally as a weapon against Americans legally opposing his re-election...
Responsible for the 1st-ever US Credit Rating downgrade...
Learning about Russian attempts to hack senior govt officials, running a counter-Intel operation using social media to successfully con snowflakes into organizing and marching for them, successfully paying willing liberal hate groups to spread racial division and violence across the US - knowing about it and allowing it to continue for 2 years un-challenged....
Whispering to Medvedev to pass on to Putin that he would me more flexible to work with him after re-election...and 2 years later giving Putin uranium, Crimea, TOP SECRET data off of Hillary's illegal server, and 2 years of un-challenged pillaging and meddling in the US...in exchange for Putin's permission to allow him to commit the International War Crime of invading a sovereign nation without that nation's request or permission in an attempt to overthrow Syria's leader, which Putin was never going to allow to happen to begin with...
...and so much more. All recorded, documented, kept for posterity. His and the Democrats' / snowflakes' attempt to hide / re-write history will fail. As you said, his legacy is cemented, and almost everything he tried to do to 'fundamentally change' the US - his attempt to write his own legacy has been all but wiped out by President Trump.
Oh, and the last 2 years of attempted coup d'état, the exposed illegal investigation opened by the FBI, the documented collusion and collaboration between Obama's DOJ, NSA, CIA, and FBI -
that began on Obama's Watch - all of that - the attempted seditious conspiracy to commit treason - gets added to Obama's legacy.
Jimmy Carter is forever in Barak Obama's debt, as Obama took the tile from him of Worst US President of all time.