Holt, if you will remember, was a Hall of Fame caliber receiver in Martz's system during the days of the Greatest Show on Turf, so bringing them together would seem to be the best fit for Holt heading into his 12th NFL season.
With Holt on board, it would take a lot of pressure off of the Bears' young receivers. Devin Aromashodu, Earl Bennett, Johnny Knox, and Devin Hester are all young guys short on experience, but certainly aren't lacking the talent to become very good receivers.
Aromashodu really broke out in the last month of the season with 22 receptions for 282 yards and four touchdowns, and could take the next step with a guy like Holt to mentor him.
Knox and Hester are two of the fastest receivers in the league, but could learn the intricacies of playing the position with Holt around. Bennett is a lot like Holt already in that he doesn't possess blazing speed or freakish athleticism, but he's just a guy who could really take the next step if shown how to play the game by a veteran like Holt.
Not only would his presence help the receivers, but it would also give a guy to Cutler who he could trust instead of simply trying to rifle the ball to Greg Olsen when things break down.
Also, the Bears could just flat-out use another receiver. The group they have now could be very good, but right now they're all very young and unrefined. Holt immediately brings the group up a notch, and could even pave the way for Hester to go back to returning kicks as well as his receiving duties.