A lot of people were moaning about quests being uncompleteable, but it seemed to mostly rotate around quest bosses not spawning when their corpses were being camped. Foulwing, the Wyrd Tree elemental encounters, and Faol-chu all caused problems for me, but resolved themselves when I got on before the majority of players (before the US woke up).
I doubt it will. Star Wars proved that having a large fan base from outside the MMO market isn't a ticket to automatic success. I'm not sure if it will be successful enough with a sub model. Most likely it will follow the Star Wars path. Players buy the box, pay for a sub, the sub model will look unlikely to be stable enough. Perhaps it will even go so far mirroring Star Wars that end-game content will be insufficient for content-hungry players reared on the endgame of WoW.
For the record, Eternity Vault in Star Wars has probably been the most enjoyable raiding I've done. It was such as shame that Karagga's Palace was incomplete, and there wasn't a hard mode at launch. They are quite clever chaps at Bethesda, and hopefully they won't fall foul of the mistakes made by another MMO.
Oh, and 5 abilities+Ultimate+Quaffing a potion is not exactly great either. My WoW rotation consists of 5 abilities. Two of the ESO ability slots are taken by familiars. One is taken by "Fill soul gem". Finally, 2 slots is hardly a rotation.