That's your playing style. Good that it works for you... For me it's a chore because I feel limeted in my options.
It's a new system.* You'll learn the ropes eventually. Once you get over the initial hurdle of unfamiliarity, a lot of the chore-ness goes away.
Maybe it's just me, but I cannot prevent someone getting smashed. That's what I used healing for. To prevent my tanks getting smashed. Croud Control + healing worked wonders for me.
Yes, it's just you. Currently playing on Hard with a standard party consisting of Cass, Blackwall, one mage (I swap between Dorian and Solas based on my mood), and me, an archer assassin. Most fights, I never have, and have never had, a problem. Of course I'll eventually run out of potions, but that usually comes after a couple hours of roaming around.
On the Combat and Strategy board, you'll find the uber-l33t players talking about how they can solo dragons or how Nightmare is too easy. I am not one of them. However, I did make use of their knowledge to construct my party and tactics. You could do the same.
* Well, not that new, since it clearly existed in GW and other games before DAI.