but at the moment the only thing I can suggest (which is obviously not that good) is to have the command in the console and press up then enter to re-enter it each spawn.
That what I do at this moment.
Hope it will be "fixed"
If you use onthefly tool you'll be able to change weapon fov hitting a key.
http://maldotex.blogspot.com/2013/02/maldo-onthefly-for-crysis-3.html
I'm working to automatic change after respawn in the next version (but I can't promise it).