The idea is fine. In theory. I wouldn't mind warfronts if they were just... better.
My biggest issue is I don't like pugs. But the system doesn't let me queue with my guild. It's not even a difficult thing to implement.
Second issue is they're too linear. You should be able to get some choices on what to build, like any RTS. If I want to build 10 Barracks and make a hundred Marines (like in Starcraft) that should be my choice to make. But currently you need the siege weapons and everything else doesn't matter, but you're still forced to build everything in order just so you can build the next thing.
Third is they're too easy. The first time I entered a warfront I was already strong enough to beat packs of 20 enemies at a time, and solo an elite commander. So building soldiers is uneccesary. The logical way to make the building portion matter is to have enemies that you can't defeat if you don't build an army. What we have right now doesn't feel like an army, more like a bunch of unorganized overpowered mercenaries sweeping through the land.