Let me say upfront this is purely speculation on my part and something I wanted to throw out there for discussion.
As much happiness as there has been in Tar Heel Nation over the ridiculous recruiting catches Roy Williams has made, there is also a every so slight undercurrent of concern over the fact UNC is stocking up on big men and not much in the way of traditional guards. Now I attribute this to the fact the pieces just fell in place that way so it looks like the Heels are overloaded at the 3-5 spots and when we reach the end of the process things will balance out.
All that being said I wonder, how much next year's extension of the three point line to 20-9 from 19-9 is influencing Roy choice of player? At first glance it would probably be a little reactionary to try and preemptively account for the impact of the extended line because that impact is totally unknown. No one knows if the shooting percentages will decline thus pushing teams to be more interior oriented in their offense. In theory moving the line out without widening the lane will create more space between the perimeter and the basket. Teams playing man-to-man will be spread out on the court more and a team with mobile big men who can work from the foul line in(like the guys UNC has committed) presumably will be better off. Of course you still need to have offensive balance with guys who can hit threes at the new distance just in case a team decides to pack a 2-3 zone. However, even a 2-3 zone stands to be less effective since the extended perimeter will require to two guards to play further from the basket opening up more space around the hoop. In the end I think you are talking about more spacing around the lane area which should create more shots in the 10-15 foot range.
At this point, if I were to hazard a guess I would say the three point shooting will be marginally affected by the change and probably only in the first season. So many of these guys are capable of shooting from anywhere within 22 feet of the hoop so I doubt we will see a drop in three point shooting in a way that alters offensive strategy for most teams. I do think the extra foot will increase the spacing around the basket since the lane is still the same width. I also think the compliment of players UNC is bringing in over the next two seasons will be effective is that spacing is there. Maybe Roy looked ahead at the rule change and decided to see if he could be ahead of the curve. I kind of doubt it but it will be interesting to see how it plays out or even if we can tell a difference from this season to the ones ahead.