1. Fully voice-acted. Sounds great, until you realize that rolling out new content is going to be prohibitively expensive. Instead of a game designer submitting ten new quests it's going to be one quest with 90% of the budget immediately tied up in hiring voice actors, processing the sound files, linking them, lipsyncing them and having playtesters run through again and again. What's that? Multiple languages? Take your budget and multiply it by ten. Also, take your normal dev time and multiply that by ten - There's your new delivery date.
2. All the same applies when it comes to branching dialogue and their associated story changes. Every branch requires twice the amount of work. A quest with just four short branches could more than double the amount of work required. Then keep in mind that as an MMO players can't simply reload to see the changes, so you are working harder to deliver the same amount of content as any other MMO. There are always alts, but once the FAQs come out you're bound to be stuck with a lot of implemented branches that nobody ever takes because they aren't seen as advantageous.
3. Everyone's a hero. Thus far, however, there has been almost no word on how grouping will work. The walkthrough shows a two-player scenario called a Flashpoint, but why not spend those millions on a flashy co-op game that doesn't have to bother with the associated MMO overhead? So far they are staying away from the usual hard roles and I definitely like that but they haven't dealt with incentivizing groups. The Star Wars mythos is about heroes who want to be on their own getting pushed together against difficult odds and so far we've seen nothing about that.
4. In the aforementioned Flashpoint there were dialogue branches. It seemed that at different points the two players were each allowed to make choices. This feels more like a tabletop role-playing game - you can't always rely on the other players to do what you would and that can generate some nice dramatic conflict. Expect this to be a very hard sell, though. Game players, especially in the MMO realm, can be a controlling bunch and asking them to let someone else guide their play experience isn't going to sit well. Also, what would happen in a larger group? Will they have to shut people out of making choices?
5. Space combat? This came far too late in the dev cycle of the original Star Wars MMO. It's an integral part of the Star Wars experience. We've seen nothing so far, but I'm not going to hold my breath.
6. Even if they pull this off they're setting the bar so high that budgets are going to skyrocket further, which means even fewer chances for any kind of novel content. I would say that a normal MMO budget including marketing and infrastructure requires at least a 200 million dollar startup. That could fund a good 10-15 AAA titles on a next-gen system. Think of what 200 indie developers could do with a million bucks apiece?
If this thing succeeds it will be amazing. If it manages longevity I'll be even more surprised; Strong central narrative structures are pretty much the epitome of just-keep-playing MMO feedback loops. If they can deliver any kind of content updates in a timely fashion I'll be absolutely blown away.