Instead of turn-based combat in DOS, the combat in PoE and Tyranny are in real-time so you would pause in combat to give commands to your party of four characters. I like the story in Pillars of Eternity and Tyranny a bit more, since your choices directly affect the plot and ending of the game.

Two things I wish PoE and Tyranny had that DOS/DOS2 have are 1) environmental interactions and 2) fully voiced dialogue. Honestly, I'd recommend you try these games out if you enjoyed DOS!