Fair or not, Lebron's status as an all-time great will at least be partially impacted by his Finals record and how many rings he ultimately ends up with.
However, these last two years of Finals losses (including another presumptive loss this year) have been devastating for two reasons - A) he's essentially handpicked and assembled these teams the last two years, even including the coach this year, and B) this has now put him at an almost insurmountable Finals record to climb out of for a winning record.
2-5 in the Finals is pretty dang poor and equates to a winning percentage of around .285. Further, three of those losses (including this one if it goes only 5, which seems most likely) would be either by sweep or a gentleman's sweep of 5 games, and the other two were 6 game series that weren't necessarily all that close, more the GS one last year than the Mavs one. What's more, there have been several games in each series where Lebron has just simply failed to take over like the best player on the planet that he supposedly is.
So how will his legacy ultimately be affected due to this fairly terrible Finals record? Personally, I think it keeps him out of the question for a top-3 all-time great, no matter what other individual records he holds. And he certainly will never pass Jordan without a major turnaround in his Finals record.
Bonus question: does he win anymore titles in his career as the main man? Will he title chase at the end of his career?