I disagree to an extent. I think environmental mechanics absolutely has a place in 5e, just not to the extent of DOS2.
Not really arguing it should be "removed". It just needs to follow the rules! Here's a great example :
https://www.dndbeyond.com/spells/create-bonfireThis cantrip creates
magical fire with the following effects:
1. Affects 5 foot square. That's the size one medium (human) person occupies on the map in tabletop. So it hits one person.
2. It does 1D8 damage and you get a
save to take zero damage.
3. You do not take damage walking through it. I repeat
you do not take damage walking through it.
4. You take damage if you stand in it on purpose by ending your turn in it.
With a save for zero damage.
They're this strict even with magical fire. Also here's another really important point:
https://www.dndbeyond.com/spells/greaseIn previous versions of the game you could set grease on fire. They specifically removed this ON PURPOSE because it was too strong in 5E.