I think it's awesome that WI hunters are going to be able to use a crossbow. I wish the IL laws would change so as to accommodate crossbows for all archers all season long. As it is now, I believe that any archery tag can be filled with a crossbow after the second firearms session has closed.
That being said, I also think WI has a good idea in how they have arranged their licenses/permits to be specific to either an upright bow or a crossbow. This method will definitely give valid data on which weapons are used to kill the deer that are reported.
However, I disagree that the overall number of deer/bucks killed will increase. Some people who use vertical bows may switch to crossbows. Some people who are gun hunters may pick up a crossbow to take advantage of longer seasons. This could cause a skew in the numbers of bucks killed by specific weapons, but I don't think a person who is accustomed to killing a certain number of deer per year is going to suddenly kill a lot more simply because a new type of weapon is available. I just don't buy into the idea that kililng a deer with a crossbow is ridiculously easier than killing a deer with a vertical bow. This is ESPECIALLY true for the faction of people who have never hunted at all (or only hunted with rifles/slug guns) who may pursue the whitetail with a crossbow. There is a HUGE learning curve when beginning hunting or transitioning from gun to ANY kind of bow. My wife has hunted for 3 years now. She has killed 1 deer, a button buck that most likely had very little conditioning to humans. I have killed 3 deer with my bow in the same number of years (and passed up on 6-8 shots at young bucks that I could have killed).
A crossbow is NOT more effective at killing a deer than a vertical bow. The only aspect of the bow that I would agree with making it easier to use is that you don't have to draw it with a deer in range. You still have to move the large/wide limbs around in the timber to get lined up for the shot. Scopes may be somewhat easier to use, but my peep sight and fiber optic pins on my vertical bow do basically the same job. As far as range goes, the average crossbow hunter may take shots out to 60 yards. But you know what, so can the average vertical bow hunter. The new technologies not only with the faster bows that are delivering more energy, but also the arrows that are designed for better downrange performance have increased the effective range of a vertical bow just as much. If you go elk hunting with a bow, a 60-65 yard shot is something (I've been told) that you should be expected to be able to make. A couple weekends ago I had a gorgeous 9 pointer feeding 71 yds (per my range finder) and broadside. The buck was completely relaxed and had no idea I was there. I drew on him for practice. I had no intention of taking a shot. However, this was not for lack of confidence in my weapon to kill at that range, but rather lack of confidence in my shooting ability. (The bow is new to me this year and I have not shot it past 40 yards) The 15-20 mph crosswind was another factor that kept me from taking a shot.
So...all in all I think it's great that there are more options out there for people who want to hunt using the weapon they would like to use. As far as harvest numbers go, I really don't believe there will be much of a difference when you look at the overall numbers. The best part about it is that there is a system in place to reliably track the numbers of deer killed by individual weapons. Therefore we should be able to have some data to back up our opinions in the next couple of years.
"When a hunter is in a tree stand with high moral values and with the proper hunting ethics and richer for the experience, that hunter is 20 feet closer to God." ~Fred Bear