Maybe I'm joining this chat late to the party, but why is a level 5 character picking Vecna's lock?
If I'm running a game and a level 5 character is in the position to pick "Vecna's lock", it's either because I wanted it to be a possibility or because the character is very much where he/she shouldn't be. If the lock can be picked at level 5, it's because I gave it a DC to make it achievable at that level. I really don't care what system you want to claim this fiction is occurring. Likewise, if in the same game the same character is picking "standard" tomb locks at level 10, they're not going to be a challenge unless there are some pretty impressive explanations to justify the discrepancy.
That's all great, but it's your DMing skills coming into play, not how the game is written. In 4e, if I was designing a 5th-level adventure that included Vecna's Very Secret Diary in it (maybe it's in the same room as the MacGuffin) and I want the PC's to have a chance to open it, maybe I'll give picking the lock a hard DC...for 5th level characters. In 5e, that same diary would be a hard DC
period. They've got a chance to open it, just as in 4e, but now that DC is a property of the item.
If later on in 4e, I've got a dungeon crawl and I want to have hard locks for the 10th-level party, I'll again use a hard DC. That'll make it harder than opening Vecna's Very Secret Diary. In 5e, that same dungeon crawl might just have locks that have a hard DC in them. Now they're as hard as opening Vecna's Very Secret Diary.
If I'm running a game with this "Vecna lock" in it, let a level 5 character crack it open, and then inform the player that it worked because I made the DC really low... well, yeah the sense of accomplishment will be tanked.
Even a DC that is high for a 5th level character will be really low for a character of 15th level in 4e. In 5e, these DC's are the same - hard is hard. In 4e, these DC's vary with the level of the character - hard for a 1st level character isn't hard for an 11th level character.
Create what problem? What intelligence level is to be assumed of the GM for any game system when written and do you assume different levels for different games? I ask because I don't understand how a GM could hose up the DC of a terrible lock in 4e and yet somehow have little to no risk of the same error in 5e.
The "tradmill" problem that can wreck the feeling of achievement. The issue isn't one lock, it's the comparison between the two challenges (and how similar they are in 4e despite the intervening levels).
I don't follow this either. If I play a game from 1 to 7 and save the world in it, I'm probably going to feel accomplished.
And I'm going to feel mechanical accomplishment too because after all I started at level 1 and made it to level 7.
Maybe you would, but there's a lot of folks who would see that and say "Hah, well, I guess these other 23 levels are completely unnecessary. Why did I even need 7? If it's just going to be the same thing with bigger numbers, this number doesn't represent me
achieving anything."
I mean, to illustrate with extremity, the DM could just declare that your characters are like unto gods and can kill demon kings on a roll of 4, and you aren't going to feel that accomplished killing demon kings because your ability to do so had nothing to do with anything you did as a player.
Mechanically, you haven't moved the needle. It's crystal clear that the DM just gives you a DC that bears no real relation to the game-world, that is calibrated exactly for your level, and that isn't related to the things you do as a player.
And if I saved the world at level 7, maybe that's the end of the campaign. Or maybe some new universe spanning threat comes to bare. Or whatever. Really just not understanding what you are getting at with this comment.
The fact that Level 7 is meaningless. The fact that you can do that at level 7 supports that point.
Why do you think this is different in 4e?
The maths are intolerant. You try hitting the AC of a level 13 monster at level 1 in 4e and tell me how it turns out.
Why do you think a 5e GM, if planning to have an encounter with a dragon for the players at level 11 due to story development, might not adjust it's difficulty?
Because they don't need to. They can just let the chips fall as they may. The DM doesn't need to know the outcome going into it - maybe folks die, maybe they get clever, maybe they run away.
The adventure that 5e uses to teach new DMs how to play - Lost Mine of Phandelver - has a CR 8 dragon in an adventure designed for characters of level 1-3 or so. It's
better because of that beyond-deadly threat.
I think you're conflating encounter design with plot design. If I have something high level planned and the PCs aren't ready for it, as a GM I decide how I want to handle it. I don't, in 4e, suddenly decide to recalibrate the opponents just because they stumbled on them. I wouldn't do the same in 5e either. But if the story is ramping up faster than expected and something is coming to a head, I may choose to adjust the difficulty of an encounter because it's more interesting and satisfying to present a feasible challenge to the party rather than either handing them their assess because they did well and advanced the plot faster than expected or coming up with flimsy delaying tactics and random encounters so they can level up for the real fight.
In 5e, you don't have to make the decision to adjust the difficulty of an encounter. You can just let the players handle the fallout. Maybe they'll handle it quite well! Maybe not. Either way, it'll be interesting!
Unsure how this is different from fighting orcs at low levels and giants at high levels in 4e. Actually, wouldn't it feel like an even bigger accomplishment because now you're going toe-to-toe with giants and can squish orcs like grapes!
The fiction isn't relevant - what's relevant is that the difficulty you're trying to hit hasn't changed. It's the same number, you're just
better at it now.
You know your 4th time through a boss fight in
Dark Souls? The boss hasn't become any easier, but you're dodging and hitting and getting its rhythm down and you used less estus to get there and you're doing better and maybe you've got it this time okay! You've become better at the game - you're a better legendary undead whatits, a better protagonist, a better hero, a better player. In 5e, that feeling comes from whiffing on svirfneblin at level 1 and solidly hitting giants at level 13. They haven't gotten any harder - your character has just gotten better at hitting.
Or it means, "if you want to challenge your players, be mindful of what numbers are challenging to them." Which is good advice for any game and any edition.
If your game wants to preserve careful balance, sure.
If your game's got no real problem dropping a CR 8 dragon into a level 3 party, the advice should rather be, "This thing will probably kill people. Have fun."