i had the same thought today a time bank after reading all the issues with sitting,sitting abuse etc. also being involved in covering clan mates and friends see if first hand.
i did a search see if had been suggested before only found this and http://www.conquerclub.com/forum/viewtopic.php?f=4&t=180120&start=0&hilit=time+bank&p=3933978&view=show#p3933978
. speed games dont count for me dont join if you haven't got the time to play it.
Anyway my point is if every player had a time bank 24hours for a 4 week period then it gets replenished or could be longer/shorter.
if your team mates or friends see that you going to miss they can add extra time for you so you dont miss,an extra 24hrs is my first thoughts counter stops when you take your turn. once timer used up then you miss would save a lot of sitting i would thought especially in the clan world.