From my quick search and bad memory, it can be played solo, but it looks like combat requires a group to enable all the feats and abilities. Doesn’t look like they’re implementing a solo build that can do it without some serious grind. But I’m sure someone will game out a solution.
I will probably still take it for a quick spin if the reviews are good, but as an old dude who can’t dedicate time to MMOs to be good at them, I’d just rather all games be made to suit my particular tastes. /s