Heya all, as the topic title says i have some questions about mage and rogue on nightmare mode to avoid easy to go run, and to have some tips from who played this class:
1) KE is always easy mode? if you skip the active barrier and pick only the barrier on damage passive is easy?
2) KE can be played both ranged and melee? or is forced to melee?
3) Rift Mage can do some decent DPS? Is less easy mode than KE?
4) Same go for Rogue archer, all specialization become easy mode?
5) The DPS of rogue is superior single target and mage is superior AOE right?
6) Mage built as dps without barrier can do some nice single target and AOE damage?
7) Only one mage with barrier in group can keep the game difficult?
Thank you all in advance and sorry for my bad english 
1 & 2 - No idea, haven't played it. From what I've gathered is that if you just stay out of the spectral blade it's not that OP. You just get a bit more defensive survivability
3 - Playing a Rift Mage now, 2nd playthrough @ lvl 13 and Nightmare. I'm having a lot of fun with Rift Mage. Mage does indeed pack a punch but not quite like a rogue. Pretty sure my rogue had slightly higher on DPS - but a rogue has limited utility and mostly single dps. As a mage you will want to shut down enemies with status effects as much as possible, which is also a lot of fun
4 - Yeah, Rogue Archer is pretty easy in terms of game mechanics. Still enjoyable though. One-shotting enemies is always fun.
5 - Pretty much.
6 - I've built my mage without barrier. I do keep Solas on my team though - it's nice to have at least one. DPS-wise I feel pretty solid
7 - Well... depends. I killed the Hinterlands dragon at lvl 13 on nightmare in not exactly epic gear. The game is not hard. Having more barrier doesn't make it easier though - it makes it slower. Wanna spend mana not dying? Or killing stuff? I prefer killing stuff
I played once as a archer rogue, turned to daggers late game. It was a lot of fun, but from a combat mechanics standpoint not that engaging in the long run. Got bored, switched to daggers, and just enemies just went *splat* when I touched them
However I hated the melee mechanics of the game. On my second playthrough I'm a purely offensive (rift) mage and I'm having even more fun!
But that's also because I play on Nightmare and the game is finally pushing back a little so I have to actually make an effort. Fear, Static Cage, Firewall etc. are great for controling the battlefield (to the degree that we're able to in this game), while laying down the hurt.