My second character is a DW rogue and I've just made it to Skyhold. So rogues kinda suck now ? I had no major problems with it until now. The only problem I have is that I don't know what skills are a must have, but some people already answered my question in this thread.
So what spec should one choose ? I'd go for the assasin. Other thoughts ?
I'm planning on killing all the dragons in my current run.
Dagger rogues do not suck. They arguably can potentially deal the most damage in the game. But they're trickier to play than other classes since they are vulnerable to damage by being in melee range and lacking heavy armor, and they require proper timing and stamina management to be efficient.
Assassin is my favorite specialization, even if the focus ability is useless. Good choice. Tempest is also a decent option, and has one of the most powerful/broken focus abilities. Artificer is the one i'd recommend the least for a dagger rogue NPC, but I guess it can be viable if you take advantage of all those traps while you're in melee.
I keep hearing to get out of Hinterlands, is it just a bad area in general?
And Perks - I bought the arcane knowledge perk.
What perks are good, what aren't?
How do you get perks? They seem like I randomly get them?
Hinterlands is not bad. If you stay too long there, you can become over leveled for some content later on. And some people argue that side quests are better in other areas. Frankly, I don't see the difference, and most of the content scales to your level, so I suggest you stay there as long as you want, and then go out whenever you want to explore somewhere new. There's way too much to explore in the game, so if you want to experience all or most of it, there's no way to avoid gaining levels like crazy.
You get a perk every time you gain an Influence level (the blue progress bar you see when you finish a quest). Perks I like are "Fine Tools" (or whatever is the name of the Secrets ability that lets you pick the tough locks) "True Grit" (especially in nightmare) "Advanced Focus and Master Focus" (if you want even more greatly overpowered focus abilities). There are also good perks for increasing your inventory space (antivan tailoring) or the amount of potions you can carry. If you're into RP and codex farming, you definitely want all the "Knowledge" abilities.