Air carrier in descent was issued a late interim altitude; overshooting the altitude; the reporter indicating resumption of the controller familiarization cockpit rides would help educate controllers regarding aircraft capabilities.

Narrative

On descent into ATL on the CANUK Seven; I was the pilot flying. The First Officer was the pilot monitoring. We were asked to keep our speed up approaching Baxly Intersection. We were later given the clearance to cross CANUK at 12;000 ft at 250 kts. We began our descent to comply with the restriction. Approximately 30 miles from CANUK; we were revised our clearance to level at FL230. Our descent rate was close to 4000 ft/min. No way could we level at FL230. I told the pilot monitoring 'Unable to Comply'. He transmitted this as we descended thru FL210. We were then given FL190. My only thoughts as to how this happened; are; controllers failure to understand aircraft level off capabilities and a possible communications overlap when we reported; 'Unable to Comply'. I know there are many new controllers due to retirements and attrition. I believe many do not understand aircraft performance capabilities. Jump seat in the cockpit for familiarization rides for controllers helped before they were banned after 9/11. Communication problems has and will be a problem in the future. Best plan is to stick with the basics. Frequency congestion in the low altitude structure is worse.