If you have been adding each of the patches, then there is only one flaw. The Ottoman Empire reform cards do not function. There is a fix for this floating around and some players have it, but the fix has not been widely shared (perhaps someone can share based upon this post). Of course, this is not too critical to play as one reform is overturned and the other caused lots of internal turmoil
The game works for mulitplayer, usually pbem, but could be face to face. There are no longer any functional breakdowns with crashes and glitches. However, a knowledge of the war helps with what some players think are glitches. If Napoleon follows an historical course with regard to such things as establishing the Confederation of the Rhine, then all the treaties will fire as intended. However, as later events depend upon earlier events firing, an ahistorical conquest/treaty may appear to be a glitch because the dependent earlier event has not yet fired. So make sure your Napoleon has a table of treaties by his/her computer. Every good war game awards players with historical knowledge over the uninformed, but this game demands that players know what Napoleon did when and where.
I have been involved in mulitplayer games since WON's release and continue even now to play muliplayer. The major issue I have found is not the game, but keeping seven players engaged. Many games end because players find their faction in trouble and quit or their life changes, like a new baby or cat, and they have no time to play.
All factions are not equal, but all are fun. I encourage all players new to WON to have Britain resist invading Spain. Sure, take Spain's colonies and sink her ships, but to really defeat Napoleon you need to force Napoleon to attack Portugal which only happens if Britain never lands in Spain. The Peninsular War rarely happens in pbem, but it should if only Britain will hold back her troops until they are needed to defend Portugal.
And, if Napoleon is keeping to schedule, the French player will want to enter Spain and annex the region around Barcelona.