question about gunner class.

[Allyrion]

Note we have no idea if its a DPS/Support like Bard is. Probably won't until June.

Most of the storyline after Prae can be done on your own, and currently most of the trials are very easy since you'll have people with you who are overgeared for them. I assume there will be "Normal" versions of atleast the Primal trials added alongside Heavensward (since currently only the first three have such, the rest are "Hard" and "Extreme" only). Chrysalis might be your first actual hurdle once you get to it.

Well, there was that interview:

How does the Machinist class work?

It’s going to be a ranged DPS. This class has different gadgets that strengthen or help itself or the party members. The first kind are the attachments, you can use these to raise your DPS to make yourself stronger. We also have turret type weapons that you can set up to buff your allies or debuff your enemies. This class is kind of like a ranged DPS meets buffer/debuffer.

Source

That sounds more like support than even BRD is.
Still have to see in practice.