Far, far off suggestion: Story mode replayability challenges.

[Own]

This is more for when the game is 100% completed, which is probably at least a year off from now. A big problem with a lot of RPGs is that, once you've beaten them, there's little reason to replay through them any way but the most OP way possible unless you self-impose challenge runs to get more bang for your buck.
I was thinking that, once you beat the final boss / did the final story bit on a save file, that file could be marked [Completed] on the main menu. Next time you select it you can choose [Continue] or [NG+ Challenge]

[Continue] puts you back in your old save, [NG+] presents you with a list of options. The first,

NewGame+: Story progress wiped, everything else maintained.

Every option below that puts all your non-cosmetic items, cards, gold, etc in a vault leaving you at level 1 with nothing else, while modifying the game in some small way to add replayability for achievements / cosmetic unlocks. Doing them on Normal unlocks rewards in Story Mode, on Hard ports them over to Arcade as well, maybe. Or not. An option in the menu lets you cancel out of the challenge at any time, to re-pick any new challenge or go into a basic NG+.

Cryomancer: All skills except Ice are locked.
Geomancer: All skills except Earth are locked.
Aeromancer: All skills except Air are locked.
Pyromancer: All skills except Fire are locked.
Summoner: Frosty Friend, Cloud Strike and Summon Plant are unlocked at the start, all other skills are locked. Your attacks do 0 damage.
Sword Dance: All skills except 1H are locked.
Heavy Hitter: All skills except 2H are locked.
Scavenger: All shop NPCs have no [Buy] button.
Two Pair: Beat the game in 2P. If you don't have a second party member, the game is still balanced as if two people are playing.
Three's A Crowd: Same a 2P, but with/balanced for 3P.
Full party: Same as 2P, but with/balanced for 4P.
One-Hit Wonder: Your current HP can't exceed 1. Immune to poison.
1-Up: One life. If you die, your story progress is wiped and your current gold / items are immediately added to the vault.
Bullseye: All skills are locked, your attacks do 0 damage. But you start with a bow and infinite arrows.
Basic: All skills are locked.
Dodge and Weave: All bosses take 0 damage from you, but slowly lose HP on their own.

Beating the game on any challenge allows you to go to the Collector's HQ and unlock your vault of items / gold / level up to your highest vaulted level immediately, or unlock it normally via a normal NG+ selection.

Or maybe I'm just the only one who would replay through the game a bunch of times with subtly different mechanics, just to unlock extra cosmetics. Rewarded replayability is always nice, though.

 

[The G-Meister]

I think people will do the skill runs if they want to anyway. I guess it encourages something different though. I'm personally against this sorta stuff unless it adds in another major mechanic to change the game complteley, otherwise it seems pointless to do this many runs just to get all the achievements.

For cosmetics alone, sure why not. Something to show off on the Arcade leaderboards is fine, but people shouldn't have to go out of their way playing until boredom to get all the achievements. My friend is an achievement hunter, and he didn't even try to beat Arcade mode. I doubt he'd go to these lengths to complete the game either

The vault sounds cool, but I'd much rather just have all the NG+ options unlocked at the start of a run once you've finished the game once, rather than have my save essentially deleted for a period once I start a new run.

The one from this list I'm really fond of is the bow one. Infinite arrows sounds like great fun, but it might end up hurting your fingers with all the button mashing. I think something else would have to be added to make it more finger friendly, such as the bow might take longer to charge, but do a bit more damage (like 2x), so we end up with a "sniper" run.

 

[Tylerthedragon]

While these challenges would be cool, unless there's a way to show off you've done them (cosmetic hats usable in arcade mode/future playthrough) then there isn't any real reason they should be added as an actual option. People who want to do those challenges will just do it themselves without the need of the modes being selectable after beating the game.

Superbosses that would increase stats would be amazing for those completionists and would help those who want to become the ultimate completionist. But I'm not against the idea of New Game +.

 

[Own]

While these challenges would be cool, unless there's a way to show off you've done them

You mean like Steam achievements?

 

[Pharphis]

I think people will do the skill runs if they want to anyway. I guess it encourages something different though. I'm personally against this sorta stuff unless it adds in another major mechanic to change the game complteley, otherwise it seems pointless to do this many runs just to get all the achievements.

For cosmetics alone, sure why not. Something to show off on the Arcade leaderboards is fine, but people shouldn't have to go out of their way playing until boredom to get all the achievements. My friend is an achievement hunter, and he didn't even try to beat Arcade mode. I doubt he'd go to these lengths to complete the game either

The vault sounds cool, but I'd much rather just have all the NG+ options unlocked at the start of a run once you've finished the game once, rather than have my save essentially deleted for a period once I start a new run.

The one from this list I'm really fond of is the bow one. Infinite arrows sounds like great fun, but it might end up hurting your fingers with all the button mashing. I think something else would have to be added to make it more finger friendly, such as the bow might take longer to charge, but do a bit more damage (like 2x), so we end up with a "sniper" run.

I was thinking the same thing, except have slow regeneration (max 30 or something) + have half-fill (ex/ 15 arrows) for every perfect guard.

I think challenges are more suitable to arcade mode or a boss rush to be honest. Playing through the entire story seems like a bit much effort for what should be a minor challenge in some cases or way to tedious in others. Multiply that by 20 challenges and I agree that it would be annoying even for people who just want a skin.

I like the idea of challenges but frankly would either like story mode to always be in beast-mode (or whatever it's called, as the new game + mode) or just have these kinds of challenges for arcade mode (with high scores for each type of run )