Sorry can't help myself. He can handle the ball and be a "point-forward" such as Paul Pressey did but he does not have the mindset to play point guard for extended periods. He might be able to play an average 5 today but if so that speaks more about the lack of quality centers than it does about Lebron's ability. The centers of the 70's-00's would have killed him. Lebron is a fabulous player and take him for what he is. I don't think either is the GOAT but great players. Regardless picture Lebron trying to guard Jabbar, Moses, Gilmore, Ewing, Hakeem, Ewing, Robinson, Duncan and Shaq, or even the Cartwrights, Mornings, Smits, or Daugherty. A possession or two caught on a switch maybe. Take an entire game and they all wear him out.
I don't entirely disagree that he'd have trouble handling the centers with these crazy skillsets, but also consider his ability to outrun all of those centers and stretch the floor against any of those guys. Also:
Jabbar = 225 lbs
Malone = 215 lbs
Gilmore = 240 lbs
Ewing = 240 lbs
Hakeem = 250 lbs
Robinson = 236 lbs
Duncan = 256 lbs
Shaq = 325 lbs
Lebron = 265 at "4" weight... I think we forget the only person on that list that would body him up is Shaq.
Here's a video of Lebron killing Gasol who, by the way, weighs 254--40 lbs more than Malone, 10lbs less than Lebron (who is also at 5% body fat). He couldn't make Lebron move an inch. I think Lebron's weight is often forgotten in these arguments.
Defense matters in the GOAT discussion, IMO. I know you love Magic, but he had some serious defensive liabilities against quicker guards and slow help defense when he was guarding shooters (John Paxon). Lebron is easily a Rodman-level defender with similar height and way more strength.
Like I said, I wouldn't call him GOAT yet, but he's the only guy in my generation that I'd say is talented enough to pull it off.