I'm going to say it because it needs to be said. Skirmish is a garbage game mode. It has potential I suppose, but as it stands now, it's essentially a game of gank or be ganked. Which means it isn't really any fun whether you're winning or losing. It doesn't take any skill to stand in a group of 3-4 people and kill one person, and skill doesn't account for much when being ganked with all of the fast unblockable shove attacks that throw you off balance and leave you wide open to attack. It's just boring, and the least fun of any game mode, not to mention one of the biggest clock busters, with the average skirmish lasting 2-5 minutes longer than any other game mode. Stop forcing us to play this garbage, and either drop Skirmish orders or drop mode specific orders in general and let us choose our own mode to collect our executions/takedowns/reknown/etc. from.
I agree removing specific orders in general. So no mode specific orders or character specific orders should be in play.
Be more creative with your orders ubi! How about X points of damage done. X points of damage blocked. X number of attacks dodged. X renown earned. Place top in your team in a 4v4 game mode. Kill X number of enemies by ganging up on them. Kill an enemy (or multiple) while outnumbered.
(ok, admittedly the 4v4 is kinda game mode specific but at least you have options between which 4v4 game mode you do it in. :P )
Come on, those are just off the top of my head. You could have loads of interesting unique orders that don't need to be class or mode dependent. You have no idea how many friends of mine have said "Oh, well, I've got to go suffer through some [insert game mode here] for my orders. Then I can play [fun game mode] with you!"
Not to mention that it's become increasingly difficult to find matches recently. If you have orders for brawls but there's only a 'low' amount of people playing brawls you might not get enough games or you might have to wait ages between games just to do that order.