I like the rewards you can get with the other three options, but they’re a bloody grind, especially once you get to the end stage. Almost exactly the same fight, over and over and over and over … and you need a LOT of time to reach each next reward level once you get to the end stage, too. Most of us don’t have blocks of hours we can spend in the hopes of getting an orb or two.
OK, Tower of Doom may not be as bad as the Raids and Invasions, and I do like the being able to work with teammates to determine scroll locations, but it’s still a bit of a grind.
Maybe you could have Guild Wars every other week, and alternate it with the other 3 events? You know, GW, ToD, GW, Raid, GW, Invasion, repeat …