Well, there are some who compare Johnson to Randy Moss, only without the baggage.
It may be a steep price to pay, but just because a team gets a bunch of picks in return doesn't necessarily make it a bad trade.
Dallas did something similar for Tony Dorsett years ago, trading a bushel of prime picks to get him. He had a hall of fame career, and the traded picks turned out to be a bunch of mediocre players.
Similarly, when N.O. traded their whole draft, and the following year's #1 and #3 for Ricky Williams, the Redskins did very little with the bounty.
Personally, having a lot of draft picks is great, but I think fans do tend to value them a bit too much at times. 4 mediocre players didn't equal Tony Dorsett. Not by a longshot. It's far more important to have a personnel staff in place that knows what to do with them. I sincerely hope Mueller is up to his past standards, or it won't matter much if we have 6 picks or 10.