I know it moves about, and why does it have to be a date, why not a day ? The next few years it's late March to mid April, so why not try it, not for 1 season but for 3 or 4 to see if it changes anything, if it doesn't then try something else.
Just about every fan moans because theyre stood around in the cold, 2/3 week gaps between meetings in the height of summer and the season dragging on too long.