It does seem an attempt by the designers to take away DM agency and give more to the players- a bit like a video game. If the player wants to hide he knows to roll a 15 and be behind cover. The cover part is more up to the DM just so the player knows before attempting to hide. This starts to go into combat rounds now where the player wants to jump out and move 15ft to attack and gain advantage. It seems we can go back and forth with jumping out making noise, jumping out breaks vision with the monster and now he is seen, or is the monster can only do something on its turn- which will be made moot by being attacked by the PC.
What about if the PC wanted to move from cover to go past the monster? The monster is 15ft away and the PC moves the 15ft and then another 15ft. Does the monster see him and can use its opportunity attack, or is the PC under the invisible condition until the monster's round where it sees the PC 15ft past him?
Seems to me that they want the rules to allow the PC to take his action while being 'invisible'.
The other problem is out of combat, which does not seem to be addressed much in where you give the PC 100% explored the castle and 2 hours have gone by, here is a copy of the map. Opposed by each room you want to explore requiring a check, where forcing additional rolls will eventually lead to failure.