I can't say too much about mage or elf, as I dropped both attempts at one point. I will say that a lot of the dialogue wasn't reviewed after adding the Dalish race, so roleplay immersion was broken for me quite a bit (without even getting to Skyhold). Mage as a class was also extremely gutted from previous games, so good luck trying to avoid slotting elemental attacks, or trying to be a Spirit Healer using Entropy and Creation spells.
I have to preface my next statement by saying I only played in normal difficulty, but I had a lot of fun with a shield Templar Inquisitor, a shield Blackwall, a two-handed Iron Bull, and a melee-oriented Vivienne (I started her with regular tactic on Spirit Blade, but dropped it after the Blade of Tidarion schematic was released). While builds and compositions for casual through hard are fairly forgiving, I have heard that nightmare requires a very specific approach.
However, I do want to point out that having your entire party affected by all of your various buffs and protections within range of each other can still be very potent and secure. Still be careful of enemy area-of-effect though.
In the end, if you are not fond of warriors, you certainly won't enjoy it as much as I did. Good luck!