Respawning was never 'removed', it was simply never in the design in the first place. Neither of the previous games in the Divinity series had respawning opponents, though Beyond Divinity did have the optional battlefields (randomly generated dungeons / quests) if you wanted more combat, experience or loot.
You may not have to grind if there are respawning opponents, but you would certainly have to keep fighting the same opponents over and over every time you wanted to head back to town to sell loot, check for equipment upgrades, complete a quest, etc.
There are a couple places in the game you can keep triggering the respawn of opponents, though.
