Lebron wouldn't be average, but it would take more for him to be considered an all-time great. The young people sh!t on the 80's-90's ball, but you cannot deny that the 90s (the greatest era of sports BTW), had relatively the same athleticism of today with better fundamentals. Players 1-12 could contribute; your backups were solid-good players. There was better competition. Jordan had to go through 15-20 HOFers to get his rings.This era where he virtually has no peers (3 of the top 5 players from his draft play on the same team), he is still putting up stats that we've seen before.
Take a look at Lebron's game. His game is quick bully ball but first, handchecking would have him working harder to get to his spots. There were also shotblockers ready to meet him at the rim, so that dunking on everyone or contorting your body mid air to avoid the charge would reduce. He has to adjust his game, but I don't know if he really wants to do that. He is playing the same role in Miami that he is in Cleveland; he should be playing off the ball more by now.
His game still has flaws. His post game is still not where you can consider him lethal. He's either gonna pass or face up and try to go around you. If he adds a turn-around jumpshot, fade-away, jump hook or even a better blind side passing game, then that is lethal.
Oscar Robertson averaged a triple double for a season, and damn near close for a couple of others, and even he isn't considered Top 5. Lebron has about 7 more than Grant Hill who stopped playing more than a decade ago.