Easy game detracts from gameplay.
I've suceed the DA:O game where i without any exploits, won, having for myself limitation of using only one companion (that means that i must use only one companion instead of 3 all the time) on Nightmare.
I used and counted every potion, every flask, used explosion/poison flasks extensively.
I timed well acquisition of needed recipies, because those flasks/grenades were vital.
That was amazing but very challenging game, and i enjoyed it.
I was pleased how my female archer looked like all the time, and i make myself sure that i go through each quest to ensure having enough level and resourses to come into next part of the game, and i even had some suboptimal armors at certain moments (mainly building on defence)
I will be trying this on my 3-4 run as 2 companion limitation Nightmare FF game. I am sure it will be fun.