There is a reason why the 727 us still used for flight planning, It burns a lot of fuel, there is large drag penalties with large fuel burns for gear down type ops. It uses EPRs with large reductions in performance for bleeds and icing gear etc. The altitude capabilities at different weights gives large penalties for weight and lets face it, modern airliners are not as hands on as was the 727.
The 727 was a practical aircraft and the exam is a practical exam. You would not be able to plan a 737/A320 operation in the same way.