Dragon age games were never difficult to begin with. If anything, I think they did a great job with High Dragons this time around!
Take DA:O for one. I soloed it as a DW Rogue, as a non-AW Mage and as a 2h Warrior. No problems at all. In DA:2 It was either no problems to solo, or otherwise faceroll, it. You just had to hump around a certain rocky boss for 140 minutes.
DA:I did a better job at balancing. If you play smart, you win. If you play bad, you die. When DA:I was released (you know.. like... last week?... er..) I was told 2 things on these forums, regarding rogues;
1) tempest was OP.
2) DW rogue was unplayable.
What do I know now?
1) Assassin and Artificer both outshine Tempest at certain points.
2) DW Rogue is a monster.
What changed between the 2 things? The game did not become easier. Nothing was patched regarding difficulty. Knowledge happened. 2 days ago people would swear Artificer was the odd one out and nobody should use it. Today I will til you artificer beats Tempest, and is only outshined by Mark of Death in Assassination.
As somebody said in another thread: It's like bringing a gattling gun to a musketeer fight.
There is also the whole AI business. It's horrible, but you learn to live with it. Once you adapt, you overcome. That's how life work, and thus how games work.
But, if you want a challenge:
No mage playthrough
No overlevel playthrough (If the recommended level is 15-19, you go at 15 maximum)
No specialization Playthrough
No crafting playthrough
Solo Playthrough
Only X class playthrough
You and varrics duo adventure playthrough
Speed run on Nightmare
Try something new. No cookie-cutter setup (1 mage + tank + 2 dps, 2 mages + 1 dps + tank). Try new builds that seem odd.
The list is endless. Crafted gear is broken, and we know it. You can get Tier 2 schematics in Hinterlands. As soon as you get Skyhold you can also get Tier 3 schematics and endgame gear. Avoiding this adds for a challenge.
I, for one, got a couple of things planned before I leave DA:I.
1) 100% playthrough on multiple classes. (2h warrior, DW rogue, archer rogue, dps mage)
2) Solo Nightmare Mage and solo Nightmare DW rogue or 2h warrior.
Sustained damage is always inferior to burst damage. The only circumstance into which sustained damage is stronger than burst is when you are solo or you don't posses in the party someone to draw aggro. In all the other cases burst damage wins hands on.
Moreover it's pbvious that on overall damage the DW rogue is a clear winner from pure numbers: daggers have more base damage than bows and they are two. Many abilities in the DW tree hit two times, for example. To not even talk of the +crit and +attack that DW rogues have (archer rogues are more based on +cunning insead) and the fact that flanking (that's one of the most powerful attributes after %attack) is much easier with a DW rogue.
Simply speaking and as I said earlier: there's not comparison if we talk of damage.
Negative. Sustained damage is perfectly viable pre-faceroll gear. At which it doesn't matter, as a High Dragon dies in 15 second flat on Nightmare as an artificer anyways. If an assassin can do it in 5, would it matter?
How is it obvious? Based on what? your feeling? By the time you get your rogue close to an enemy, I have killed the whole pack. Obviously a DW rogue will burst down a single archer faster than an Archer Rogue -- but by the time the DW rogue reaches the archer the Archer Rogue has killed 2 archers and a mauler.
I love both classes, and feel they both compare in damage. Saying "There's not a comparison" requires numbers. Without it, what you say doesn't hold up. An Archer rogue holds up to a DW rogue. Sustained damage is not inferior to burst, unless we get to the point stuff dies in a second. At that point, however, it's irrelevant who is better -- stuff dies in seconds flat.
Both a dw rogue and an archer rogue want crit and crit damage. Flank is outshined by attack%, and rarely worth the time. By the time you can use that flank, the archer got 6 arrows stuck into 3 dead targets.
My point is simple: They are comparable. They both do good dps. The DW rogue annihilates enemies 1 by one. The Archer murders them long before the melee reaches them. I am happy to discuss numbers and theorycraft with you -- but I don't like assumption which is without any facts.