Too many scrolls was mentioned in the OP but that's consumables in general. Exploding arrows, grease bottles, bombs.. and most of all MAGIC FOOD that heals. That's a huge change to 5e healing economy and it's silly.
Resting system is another big topic. Long rests are fast and convenient, there is no need for Short Rests or resource management in general when getting back to full resources is behind an always available button. Bad for immersion when you can teleport back to your pocket dimension camp from anywhere even if you can't realistically return or it's dangerous.
Thirdly, the easy advantages you get in combat from backstabs and high ground throwing 5e balance out of whack is a big discussion.