NA Thornblade was very fun for two weeks. Every faction was pretty evenly matched in points. AD usually took the lead during the week, but DC and EP could even it out on the weekends. Overall, it was a fun experience.
Then one day AD started to dominate. Within 2 days, the point gap increased to where lots of the EP players felt that all the hard work they put in the last 2 weeks was lost. They moved over to Chillrend because it was pointless to play on Thornblade anymore. With half of the hardcore EP gone, there was no longer a 3 faction balance.
Had this been a 5 day campaign, this imbalance would have been solved in two ways.
First, since the campaign is only 5 days, if one faction happens to be dominating, you only have to wait a few days and then everything will reset. Clean slate. Fresh start. Two weeks of work would not have been wasted.
Also, 5 day campaigns provide an interesting rotation. Sometimes the 5 days includes the weekends (Fri, Sat, Sun, Mon, Tues). This means more players can be online during most hours of the day unlike weekdays where most players only play at night. This would eliminate the chance of one faction dominating during the "off hours" simply because the off hours are shortened. Sometimes the 5 day rotation would fall during the week (Mon, Tues, Wed, Thurs, Fri). When this happens, the faction with the largest population on the off hours will win. However, as soon as the next 5 days rolls around, the other factions are back in balance.
I did not like short campaigns at first (which is why I homed the 30 day campaign). Now, I think ZOS was correct in trying to get players to try shorter campaigns.