Very cool. This kind of limits it it though:
"a person may take deer with a .45 caliber or larger air-powered gun."
Yes, but I don't think it's an irresponsible limit, just a poorly implemented one. I would rather have it written as "500 ft-lbs" than tying it to caliber. 500fpe is the minimum for handgun deer hunting in IL, so I think it would make a good starting point for getting an airgun bill to pass.
I actually think they did the right thing- is it ideal? No, but...
This ensures legislation allowing a larger-bore airbow still will be allowed once legislation catches up. Especially since in most states, a 40-pound draw bow can be used to harvest deer. Translate a 40 pound bow with a typical 10-grain-per-pound arrow... That means much lighter tackle and energies for harvesting deer using so-called primitive methods. Now equivocate to an airbow... Large-bore ensures appropriately-sized equipment (better overkill than underkill)
It also ensures Johnny Nitro-Piston with his 1400 FPS (with PBA AMMO!) gas-piston rifle doesn't go "deer hunting" with his latest .25 caliber "big bore" springer ... with enough margin of error to set a firm foot that NO springer can be used.
In other words, it's a step in the right direction. Perfect? No, but it does set an expectation, as well as opening the door to ensure the bottom-feeding public that like to bend rules don't go out deer hunting with under-sized equipment.