Full AC Express trains are the future of IR :)
There are so many trains where AC Classes touch WL on 60 Days ARP itself clear indicator of the demand in AC Classes,
Consider the example of Mumbai-Delhi-Mumbai which is definitely the most demanding long distance sector
On any Tuesday there are 5 Full AC trains - BDTS-DEE GR/LTT-NZM AC Exp/BDTS-NZM GR/BCT...
more... Raj/AK Raj and all of them are high in demand and run with WL and still the regular M/E trains are not counted, AC demand in this sector is the highest and it will only continue to increase with time
Other recent AC Express introduced also are performing well like BDTS-BHUJ/LTT-KYQ, So that speaks something for other sectors as well...