More notes on this:
Things certainly get increasingly bad at start of war if a nightmare (ops in general) wave is happening. Getting an attack request in is like playing roulette since you are competing with the horde of ops spam.
Possible temporary fixes:
1) don't arrange wars via war requests as the server can not handle the traffic at the start.
2) devs implement a request priority (if this is technically possible) so that War Room has priority over Mystics and Thievery.