Interesting, I know of storms that damaged the Greek fleets, but I though Xerces had to return to put down a possible rebellion in Babylon and the army he left in Greece was unable to maintain the gains he made. Also the number of men in his army is up for debate. Writers of the time talk about 1 million warriors, while modern estimates range from a mere 60,000 to 500,000. I think the main contention is that given the nature of the Greek City States they would not have been able to hold out in any way against a united army of 1 million solders.
But getting back to things, this is not intended to be a historical simulator. Some people would find fun in this feature, particularly those of us addicted to games like Dwarf Fortess, but by and large I think people on the receiving end would find it decidedly not fun.
I don't think anyone would ever think it's fun, but then again, losing a battle isn't really that fun. I think the important aspect would be the extreme scarcity of such events (maybe once per year per continent). There is some events that echo this like droughts which only last for 7 days, I just think that it would enrich the history. (and again, you may be correct that I may not think so if my realm was on the receiving end of the event).
It could also be quite localized, like heavy rains on a battlefield that would render infantry quite impaired since they are stuck in the mud. Again, being on the receiving end may be infuriating, but it has happened in the past.
Best regards,
