No player is as important to their team's success as Lebron is to any of his teams for over a decade. He is still the absolute best player on the planet. He should have won 8-10 MVPs already but like MJ before him, he hasn't because the voters just won't do it. Lebron is the MVP.
I don't think that's what the award is, though. It's not a recognition of which player is the most talented or who is at their best when giving full effort. The history of the award doesn't square with the notion that it's meant to go to the agreed-upon alpha dog of the NBA.
The bottom line for me with LeBron and the MVP is that it's a regular season award and he very obviously is not playing at his full effort during the regular season. He hasn't for a few years now. I don't blame him at all for that, but I don't think he is the MVP of the league for the regular season.
He's certainly capable of playing great on both ends, but during the regular season he has operated mostly as an offensive star with limited defensive responsibilities. His team doesn't have the personnel to get by on the defensive end without him in superstar mode on that side of things, which is why they aren't playing to their potential.