I am still in it. I finished Abyss a couple days ago and then went to take Suledin Keep to try and unlock more stores to buy things.
With the restrictions, it seems like the game scales more unevenly, or maybe I just don't know what I am doing. 
For example, I did Wicked Eyes at 13 or so, took Cass, Dorian and Solas and everything was relatively trivial. So much so that I didn't notice I forgot to equip Cassandra's sword and shield in the first section. Whoops.
I did Adamant at 15 (squad was 14). Blackwall, Dorian and Solas. Adamant itself was annoying since I had to constantly swap staves to do decent damage, but except for one room in the fade with 2 Rage demons and a trillion wraiths, just rolled through. Dual Static Cages and a bunch of Stone Fists and Energy Barrage is pretty good against Nightmare.
I went to clear Emprise after that. Most of it was smooth. Suledin Keep was annoying though. The two giants especially. I think my gear was getting long in the tooth. Cass's armor was the one you get from Shimmering Mine that is Level 13 restricted. The two giant encounters are probably my least favorite fights in the game, especially because of the way the level is designed around them with uneven ground. Imshael seemed to take longer than I expected, but maybe that is because I am used to dropping bees on him. Also didn't have any great damage abilities against guard and so that took extra time against his Pride form.
In any case, I am just messing around trying to get gold and find decent gear. That is what is annoying in runs without crafting. The decent items you can buy are pretty expensive relative to the gold you can find without exploits, even if you sell nearly every item and material you find and pick up. But even if you were to dupe items to make gold fast, you will still wait for something to show up in stores. I saw a decent masterwork armor for Cass in a store, but didn't have nearly enough gold. You go to make gold, and when you return it is gone.
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As far as actual builds and strategy, Rift Mage is pretty powerful, and I am happy with it. My actives are Energy Barrage+, Static Cage+, Fire Mine+, Frost Step+, Stone Fist+, Veil Strike, Barrier and Mark of the Rift. Although I will swap Barrier and Immolate from time to time, I don't really use either very frequently.
Usually to start most encounters all I do is go Cage and then start hitting them with whatever I have. Usually drop a FM and see if Solas can send in a SF for weaken. Energy Barrage for eldritch detonation and more shocks / procs of cage. Taking Suledin I didn't have Twisting Veil and my staff was crappy so FM wasn't doing enough damage against RT mooks, just mainly pissing them off.
I actually prefer the lightning staff on this character because I like getting a lot of Nightmare or Rupture combos. I haven't noticed too many problems with mana. I am not running CL because it is basically unusable with FF on.
I tried briefly yesterday running POTA, but I prefer Cage.
One of the things that was an issue in Emprise in Suledin and moreso in Sahrnia quarry was that it seemed like Horrors would always want to target me right away, even when I sent in Cass way ahead. Not sure what their deal is, but I would have to break LOS. And it was getting irritating, so that is part of why I am even in the Spirit Tree for Guardian Spirit.
I also tried to fight Kaltenzahn while I was there (18 inq/17 party), but it looked like it would be extremely tedious with my current weapon setup and the squad I had at the time (Cass, Sera, Solas), so I just didn't bother more than once to see what would happen.