I'm from IL, and I hunt both bow and gun. Just curious, what are the "new dates" they changed your season to? I really do enjoy the fact that I get to bowhunt from Oct 1 until the weekend before Thanksgiving before the first hard core gun season. They seem to throw in some youth season gun hunts and things, but those are generally just 2-3 day sessions and only youths can shoot deer. There are a lot of doe only late season hunts in different counties and such. I really like that you can pattern deer on their feeding patterns during the early season, then watch and keep hunting as the rut gears up and still have a good chance at getting close enough with a bow to harvest a mature buck. This is all before the deer get exposed to the "orange army".
One thing the OP didn't mention is that IL doesn't allow the use of any rifles outside of single shot muzzleloaders. Our firearm season is shotgun only. I'm pretty sure you can use handguns that have the right specs as well, but the range is really limited compared to a rifle. I think this is another reason we have a reputation for bigger and older bucks.
One thing about IL that I don't like is that a bow tag is good statewide, but a firearm tag is only good in a specific county. I buy tags to hunt where I live, but if I want to gun-hunt with my dad and brothers I have to buy another tag for that county...but I can only shoot 2 antlered deer per year regardless of the weapon or county taken in...
"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