Why not remove the dungeon failure penalty of decreasing the key’s rank by 1? I think it should be reward enough completing a key at a difficulty and if it is not timed, just let them keep it at the level they are.
I mean that’s almost like wiping on a mythic boss makes you have to clear a heroic boss to continue, makes little sense.
Leave the choice for the player in the game if they want to ‘drop’ the key, but remove the failure penalty, doesn’t really seem to be any particular reason besides making dungeon life more difficult to be honest and I think it’d be a nice quality of life change that everyone would like.
Raid bosses can only be killed once a week, while you can spam M+ as long as you have time.
I certainly don’t know the devs’ rationale for the key level decrement on starting the timer (only increments if you complete in time, if you start timer and look in your bag it’s already down one). However, I suspect the fact M+ can be repeated while Raid bosses can not, is related to their design decision.
Because if you’re at the right level, you’ll bounce between the two. Time a 15, go 16. Fail a 16, go 15. Eventually you’ll know to just drop your 16 to a 15 at the start.
As soon as valor becomes uncapped, high ilvl key runners looking to farm valor quickly may benefit from spamming +2s rather than a higher key (also assumes 3 vault slots have already been opened).
I’m not sure what that has to do with the key decrementing when you start the timer (or not decrementing as the OP proposed).
Edit: spamming 2s for valor probably won’t be a thing in 10.1, since valor is replaced by Crests & Flightstones. I’m hoping the amount of Flightstones for a +16 is not the same as a +2, but we’ll see.
That descrbes how it works, but a rationale for that design decision would explain why, not how. Like the Game Director saying "Since M+ is repeatable, while Raid bosses are not, we felt a small penalty to the key level as the default outcome was appropriate. "
I don’t know of such a rationale, and obviously I made up the example above.
Edit: Ajora gave an alternative rationale like "Due to the difficulty increasing with key level, we decement the key by default assuming the group is already able to make the timer at a lower level. If the group times the key it is incremented to offer an ever-increasing challenge. "
The design of keys bricking was originally that instead of getting a key of a lower level, you’d get a depleted key of the same dungeon which had to be timed to replete it and get loot.
This was changed because people didn’t really like the idea of running the same key again to replete the key (depleted keys gave zero loot) and that key would be considered “bricked” for the week.
Then Blizzard changed it to -1 instead of bricking and it’s been that way since. I don’t think they’ve explicitly mentioned that the repeatability for why keys have to be failed, but there’s plenty of reasons that that could be the case, the repeatability of the content being my most likely answer.
As for the actual mechanic of keys going -1 when a key starts, that’s just function over form. It was probably the easiest way of programming key failures.