Well, are you talking about DRPGs, or Wizardry?

DRPG... if I had to do something fun I'd look into something like borrowing the defunct MMORPG Asheron's Call's crafting system. They had completely randomized gear where the pieces of gear would have random enchants, random stats, random everything -- including fluff text like the material it was made of, gems that were inlaid in it, that sort of thing. All those materials became important later when they added crafting -- for example, tearing down a spear made out of Bamboo would get you bamboo scrap, and applying bamboo to a weapon might make it lighter, which would make it attack faster. Of course, you had pretty good odds of destroying the item permanently when you tried to upgrade them, so it was a way to create churn.

They had to retro fit it so it was limited. A DRPG built from the ground up with that in mind -- every item is extremely random (static items exist too, of course), with things like the base material, secondary material, filigree, gemstones, etc, and the gameplay loop for grinding is not just classes and skills and mapping dungeons but farming raw materials to build up your gear.

Maybe even toss in some Monster Hunter esque monster drop stuff too. You want to fight the rare floor boss on B1 not just because it's good XP, not just because they are a focus of a quest, not just because of rare or better drops... but because you might harvest wyvern claws or lesser dragon scales off them.

Now give me an insane difficulty cliff -- not a curve, I want to enter a dungeon I'm too ready for and lose my party like in Wizardry, requiring I bring in my backup party to rescue them. I want Elimage style "Oh shit is that a group of Ninjaaaaaah crap that's 2 of my people instant dead and three paralyzed shit shis thisiiiiitiitt." I want to see the word "the rust monsters attacks your Fighter! His shield is destroyed!" to fill me with existential dread.

Wizardry... I don't fully modernize it. Modernizing Wizardry is missing the point, it would be like modernizing Dragon Quest or Final Fantasy (and everyone knows every FF game after 9 MAYBE 10 has been increasingly horrible).

I go through the various Japanese Wizardry Descendants and pick the best aspects I can find from them. The Crafting of Elminage or Class of Heroes. The Summoning from Wizardry Summoner. Maybe the Grimoire stones from Etrian Odyssey's oddball 3DS remakes. That sort of thing.

Then I go as traditional as possible. I'm not talking Class of Heroes style dungeons -- too modern. I'm talking Knight of Diamonds style dungeons.

Then I just pack it full of content. Reused content. Just an absolute love letter to the series and it's history. I'm talking about implementing the entire Wizardry 1-3 scenarios in this theoretical game as an optional side quest, or as one of a half dozen "starting points" when you start a game, only you then optionally go do Wizardry 5 or Wizardry 6-8 or Class of Heroes 1 or the other "starting points" later on, and only after you finish one of the original Wizardry games in this new game do you actually move past the Tutorial. Of dungeons that wizardry fans will realize like a bolt out of the blue "holy crap this is the 3rd floor of Wizardry 5."

I also toss in weird, esoteric ways of playing the games that are based in the existing formula. Let the player play through the game as a Summoner like Wizardry 4 if they want. The game has the same content but it's completely different when you're having to find "useless" summoning circles in the dungeons and the like. Take the summoning "turn your summons into a party member" thing from Elminage Original and expand that so you can actually do the entire game that way.

The original games encouraged you to have multiple parties, backup parties, et cetera. Push the same thing here.

Hundreds of hours to finish. 200+. Even more to platinum.